Endotracheal Intubation

Indications for Endotracheal Intubation and Invasive Mechanical Ventilation (see Airway Management and Invasive Mechanical Ventilation-General)

Inability to Maintain Airway Patency and/or Reflexes

Upper Airway Obstruction

Lower Airway Obstruction

  • Airway Mucous Plugging with Inability to Clear Secretions
  • Massive Hemoptysis (see Hemoptysis)

Respiratory Failure (see Respiratory Failure)

Type I Hypoxemic Respiratory Failure

  • Acute or Chronic Hypoxemic Respiratory Failure

Type II Hypoxemic, Hypercapnic Respiratory Failure

  • Acute Hypoxemic, Hypercapnic Respiratory Failure (Acute Hypoventilation, Acute Ventilatory Failure)
    • Decreased Ventilatory Drive
    • Decreased Ventilatory Output Due to Neuromuscular Disease
    • Decreased Ventilatory Output Due to Excessive Ventilatory Demand
  • Chronic Hypoxemic, Hypercapnic Respiratory Failure (Chronic Hypoventilation, Chronic Ventilatory Failure)
    • Decreased Ventilatory Drive
    • Decreased Ventilatory Output Due to Neuromuscular Disease
    • Decreased Ventilatory Output Due to Excessive Ventilatory Demand

Technique

Airway Management

Types of Endotracheal Tubes

  • Single-Lumen Endotracheal Tube
  • Rusch Endotracheal Tube: reinforced endotracheal tube
  • Double-Lumen Tube: dual-lumen endotracheal tube used for single-lung isolation (during cardiothoracic surgery, for management of severe hemoptysis, etc)

Adverse Effects/Complications of Endotracheal Intubation and Invasive Mechanical Ventilation (see Airway Management and Adverse Effects and Complications of Endotracheal Intubation and Invasive Mechanical Ventilation)

General Comments

  • Medical Malpractice Related to Adverse Events/Complications of Airway Management and Endotracheal Intubation
    • Inadequate Ventilation, Esophageal Intubation, and Difficult Endotracheal Intubation are the Most Common Mechanisms of Respiratory Adverse Events/Complications Associated with Endotracheal Intubation/Mechanical Ventilation by Anesthesiologists (Anesthesiology, 1991) [MEDLINE]
  • Risk Factors for Adverse Events/Complications of Airway Management and Endotracheal Intubation
    • Performance of ≥3 Intubation Attempts was Associated with a Significantly Increased Rate of Adverse Events (35% vs 9%) in the Emergency Department (Ann Emerg Med, 2012) [MEDLINE]
    • Patients Requiring 1 Intubation Attempts Had a 14.2% Adverse Event Rate, Patients Requiring 2 Intubation Attempts Had a 47.2% Adverse Event Rate, and Patients Requiring 3 Intubation Attempts in the Emergency Department Had a 63.6% Adverse Event Rate (Acad Emerg Med, 2013) [MEDLINE]

Immediate Adverse Effects/Complications (Manifest During or Immediately Following Intubation)

Arrhythmia/Cardiac Arrest (see Cardiac Arrest)

Clinical
  • Atrial Fibrillation (AF) (see Atrial Fibrillation)
  • Cardiac Arrest (see Cardiac Arrest)
    • In Emergency Endotracheal Intubations Performed in Critically Ill Patients Suffering Deterioration, the Rate of Cardiac Arrest was 1 in 50 and was Associated with Hypoxemia in 83% of Cases (and 63% of the Cases of Hypoxemia were Associated with Inadvertent Esophageal Intubation) (Anesth Analg, 2004) [MEDLINE]
    • In Emergency Department Intubations, Early Post-Intubation Cardiac Arrest Occurred in Approximately 2% of Cases and was Associated with Preintubation Systolic Hypotension (PLoS One, 2014) [MEDLINE]
    • In Intubations of Critically Ill ICU Patients, Post-Intubation Cardiac Arrest Occurred in 1 of 40 Procedures, Had High Immediate and 28-Day Mortality Rates, and was Associated with Defined Risk Factors (Crit Care Med, 2018) [MEDLINE]
      • Absence of Preoxygenation: odds ratio 3.584 (1.287-9.985)
      • Pre-Intubation Hypotension (SBP <90 mm Hg): odds ratio 3.406 (1.797-6.454)
      • Pre-Intubation Hypoxemia: odds ratio 3.991 (2.101-7.583)
      • Age > 75 y/o: odds ratio 2.251 (1.080-4.678)
      • Obesity (BMI>25): odds ratio 2.005 (1.017-3.951)
  • Pulseless Electrical Activity (PEA) (see Pulseless Electrical Activity)
    • Typically Occurs Due to Initiation of Positive-Pressure Ventilation in a Patient with Shock
    • Pulseless Electrical Activity was the Most Common Rhythm in Post-Intubation Early Cardiac Arrest (Occurred in 78.1% of Cases) (PLoS One, 2014) [MEDLINE]
  • Ventricular Fibrillation (VF) (see Ventricular Fibrillation)
  • Ventricular Tachycardia (VT) (see Ventricular Tachycardia

Atelectasis/Mucous Plugging (see Atelectasis)

Mechanism
  • Large Airway Mucous Plugging, Resulting in Obstructive Atelectasis
Diagnosis
  • Bronchoscopy (see Bronchoscopy): useful to rapidly assess for large airway mucous plugging
Clinical
  • Increased Peak Airway Pressure (PIP) on Mechanical Ventilator (When Using a Volume-Cycled Ventilation Mode) (see Invasive Mechanical Ventilation-General)
  • Unilaterally Absent Breath Sounds on the Obstructed Side

Auto-Positive End-Expiratory Airway Pressure (Auto-PEEP or Intrinsic PEEP) (see Invasive Mechanical Ventilation-General) (Am Rev Respir Dis, 1982) [MEDLINE]

Risk Factors for the Development of Auto-PEEP
  • Airway Obstruction with Expiratory Flow Limitation (Due to Asthma, COPD, etc) (Crit Care Med, 2000) [MEDLINE]
    • Expiratory Flow Limitation Impairs Exhalation and Lung Emptying
    • Expiratory Flow Limitation is More Prominent in the Supine Position than in the Semirecumbent Position (Am J Respir Crit Care Med, 1994) [MEDLINE]
  • Expiratory Flow Resistance (Due to Small Endotracheal Tube, Kinked Endotracheal Tube, Ventilator Tubing, Exhalation or PEEP Valve, or Patient-Ventilator Dyssynchrony)
    • Expiratory Resistance Impairs Exhalation and Lung Emptying
  • High Minute Ventilation (VE)
    • High Minute Ventilation (VE) May Due to Any/All of the Following
      • High Set Respiratory Rate (RR) on the Ventilator
      • High Patient-Driven Respiratory Rate (RR) (Due to Fever, Sepsis, Pain, Agitation, Anxiety, etc)
      • High Set Tidal Volume (VT) on the Ventilator
      • High Patient-Driven Tidal Volume (VT) (Due to Fever, Sepsis, Pain, Agitation, Anxiety, etc)
  • High Inspiratory/Expiratory (I/E) Ratio
    • While the “Normal” I/E Ratio for a Normal Spontaneously-Ventilating Patient is 1:2, a “High” I/E Ratio Cannot Be Numerically Defined for All Patients, Since Patients with Significant Airway Resistance (i.e. Airway Obstruction Due to Status Asthmaticus, etc) May Develop Auto-PEEP Even at a Relatively “Normal” I/E Ratio
  • Time-Constant Inequality of Lung Units
    • Some Lung Units (Especially in the Setting of Airway Obstruction) Empty Heterogeneously, Resulting in the Development of Auto-PEEP Even at a Relatively Low Minute Ventilation (VE)
  • Altered Respiratory System Compliance (Due to Expiratory Muscle Activity): impairs exhalation
    • Altered Respiratory System Compliance May Also Interfere with the Accurate Measurement of Auto-PEEP (Am J Respir Crit Care Med, 1995) [MEDLINE]
Physiology
  • Next Ventilator Breath is Triggered Before the Airway Pressure Returns to Baseline (i.e. Zero)
  • Unlike Applied PEEP Which Distributes Evenly, Auto-PEEP Distributes Predominantly to Lung Units with the Highest Airway Resistance and Lowest Compliance (Chest, 1995) [MEDLINE]
Diagnosis
  • Auscultation (or Palpation) of Continued Expiratory Airflow at the Point When the Next Ventilator Breath is Initiated
    • Physical Exam Has a Positive Predictive Value of 95% and a Negative Predictive Value of 58% in Detecting the Presence of Auto-PEEP, Suggesting that it is Useful to Diagnose Auto-PEEP, But Not to Rule Out Auto-PEEP (Am J Respir Crit Care Med, 1999) [MEDLINE]
  • Observation of Pressure Waveform Not Returning to Baseline Between Breaths
  • Expiratory Hold (0.5-1.0 sec) on Ventilator (i.e. Occlusion of Exhalation Port on Ventilator)
Clinical Effects
  • Dynamic Hyperinflation Amplifies the Respiratory Variation of Arterial Pulse Pressure and Contributes to Pulsus Paradoxus in Mechanically Ventilated Patients [MEDLINE]
  • Dyspnea (see Dyspnea)
  • Hypotension (see Hypotension)
    • Due to Decreased Venous Return to the Right Side of the Heart, Resulting in Decreased Cardiac Output (Especially in the Setting of Hypovolemia)
  • Increased Risk of Barotrauma (Mainly Due to Increased Lung Volume): see below
  • Increased Work of Breathing
    • Due to the Fact that the Patient Must Overcome the Residual Positive Airway Pressure to Generate a Negative Pressure Deflection to Trigger the Next Ventilator Breath
    • Due to Ventilation at High Lung/Chest Wall Volumes (Lung and Chest Wall are Less Compliant at High Lung Volumes)
  • Introduction of Errors in the Measurement of the Mean Alveolar Pressure and Static Lung Compliance (Am J Respir Crit Care Med, 1996) [MEDLINE]
  • Introduction of Errors in the Measurement of Pulmonary Capillary Wedge Pressure (PCWP) (see Hemodynamics)
  • Patient-Ventilator Dyssynchrony: see below
Management
  • Treat Airway Obstruction
  • Increase the Inspiratory Flow Rate and/or Decrease the Respiratory Rate (RR) to Decrease the Inspiratory/Expiratory (I/E) Ratio (to 1:3, 1:4, 1:5, etc)
    • This Lengthens the Expiratory Time, Allowing a Longer Duration to Expire the Gas in the Lung
    • In Rare Cases, Transient Removal of the Patient from the Ventilator May Allow Gas Emptying from the Lungs
  • “Permissive Hypercapnia” (Decrease the Respiratory Rate and/or Tidal Volume to Purposely Underventilate the Patient): allowing the pCO2 to increase to as much as 70-100 mm Hg
    • Physiology
      • Permissive Hypercapnia was First Utilized in Status Asthmaticus
      • Permissive Hypercapnia Decreases the Tidal Volume (VT) (Which Will Decrease the Total Volume of Gas Which Must Be Exhaled During Expiration) and the Respiratory Rate (Which Will Allow a Longer Expiratory Time)
    • Contraindications
    • Technique
      • Maintenance of pH >7.2 Can Be Achieved with Either Sodium Bicarbonate (or Tris-Hydroxymethyl Aminomethane, THAM) Administration: however, sodium bicarbonate administration may be ineffective in increasing the pH in this setting
      • Many Patients Require Deep Sedation (and Paralysis, if Necessary) to Maintain a Low Minute Ventilation (VE)
  • Measures to Decrease the Metabolic Rate (Decreasing Carbon Dioxide Production and Therefore, the Ventilatory Demand)
  • Measures to Decrease the Expiratory Flow Resistance
    • Use Larger Diameter Endotracheal Tube
    • Frequent Suctioning
  • Use Synchronized Intermittent Mandatory Ventilation (SIMV) Mode to Decrease Breath Stacking, Instead of Assist Control (AC)
  • Application of Extrinsic PEEP: this may decrease the amount of auto-PEEP
    • Mechanisms
      • Decreases Dynamic Airway Compression
      • Counteracts the Critical Closing Pressure that Causes Small Airway Collapse in Asthma/COPD
    • Technique
      • Add PEEP to the Point Just Below Where the PIP and Plateau Pressures Start to Increase
      • Use Extrinsic PEEP in an Amount <50-80% of the Amount of Auto-PEEP
    • Clinical Efficacy
      • The Efficacy of Applied PEEP in Decreasing Auto-PEEP Depends on the Level of PEEP Used and Whether Flow Limitation is Present
      • Applying PEEP to Lungs Without Flow Limitation Simply Distends Them Further and Can Cause Barotrauma or Hypotension

Bronchospasm (see Bronchospasm)

Epidemiology
  • In Patients with Underlying Reactive Airways Disease, Postoperative Bronchospasm Occurs Commonly with Endotracheal Intubation (Masui, 1995) [MEDLINE]: bronchospasm occurs in 8.9% of patients with reactive airways disease undergoing endotracheal intubation with general anesthesia
  • In Patients with Underlying Reactive Airways Disease, the Incidence of Postoperative Bronchospasm was Higher with Thoracic/Abdominal Surgery (39.5%), as Compared to Other Surgeries (10.4%) (Masui, 1995) [MEDLINE]
Mechanisms
  • Aspiration of Acidic Gastric Contents During Intubation, Resulting in Airway Irritation
  • Underlying Obstructive Lung Disease
Clinical
  • Increased Peak Airway Pressure (PIP) on Ventilator (see Invasive Mechanical Ventilation-General)
    • Increased Peak-Plateau Pressure Difference (≥5 cm H2O): reflecting an increase in airway resistance
  • “Shark Tooth” Pattern on End-Tidal CO2 (see Capnography)

Dental/Lingual/Orolabial/Pharyngeal/Laryngeal Mucosal Injury

Epidemiology
  • Common (Int Anesthesiol Clin, 1989) [MEDLINE]
Mechanisms
  • Trauma Caused by Bite Block, Laryngoscopy Blade, Endotracheal Tube Metal/Plastic Stylet, or Endotracheal Tube
Clinical
  • Oropharyngeal Bleeding

Emesis with Aspiration (see Aspiration Pneumonia)

Epidemiology
  • May Occur When Endotracheal Intubation is Performed in the Presence of Gastric Contents
Physiology

Endotracheal Tube Cuff/Ventilator Circuit Leak

Mechanisms
  • Defective Endotracheal Tube Cuff System
    • Laceration of Endotracheal Tube Cuff (Typically on the Teeth During Intubation)
    • Puncture of Pilot Balloon
    • Puncture of Pilot Balloon Tubing
  • Intact Endotracheal Tube Cuff System
    • Discrepancy Between Endotracheal Tube Size and Tracheal Diameter (Especially in a Patient with Tracheomalacia, etc)
    • Endotracheal Tube Cuff Underinflation
    • High Peak Airway Pressure (PIP): may result in leak around the endotracheal tube cuff
    • Inadvertent Tracheal Placement of Nasogastric/Orogastric Tube (see Nasogastric-Orogastric Tube)
    • Proximal Migration of the Endotracheal Tube
    • Ventilator Circuit Leak
Diagnosis
  • Check Endotracheal Tube and Ventilator Circuit for Disconnections or Leaks
  • Monitor Endotracheal Tube Cuff Pressure with Manometer
  • Bronchoscopy (see Bronchoscopy): useful to rapidly determine the location of the endotracheal tube tip, in cases where endotracheal tube proximal malpositioning is suspected
    • With a Suspected Cuff Leak, if the Endotracheal Tube Tip is in the Appropriate Position, This Makes the Diagnosis of Endotracheal Tube Cuff Rupture More Likely as the Etiology
Clinical
  • Endotracheal Tube Cuff Leak
    • In One Study of Patients with Lost Volume on the Ventilator and Suspected Endotracheal Tube Cuff Rupture, 61% of the Leaks Were Actually Due to Endotracheal Tube Dislodgment and Only 39% Were Due to a Ruptured Cuff (Crit Care Med, 1993) [MEDLINE]
    • Audible Leak from Air Passing Through Around the Cuff of the Endotracheal Tube
    • Decreased Peak Airway Pressure (PIP) on Ventilator
    • Extent and Leak and Patient Tolerance of the Endotracheal Tube Cuff Leak are Variable (Anesth Analg, 2013) [MEDLINE]
    • Inability to Maintain Endotracheal Tube Cuff Pressure
    • “Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume)
  • Ventilator Circuit Leak
    • Decreased Peak Airway Pressure (PIP) on Ventilator
    • “Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume)
Treatment
  • Endotracheal Tube Cuff Leak
    • Pilot Ballon Tubing Can Be Repaired in Select Cases Using a Commercially-Available Kit
  • Ventilator Circuit Leak
    • Replace Ventilator Circuit Tubing

Endotracheal Tube Tip Malpositioning

Epidemiology
  • In One Study of Patients with Lost Volume on the Ventilator and Suspected Endotracheal Tube Cuff Rupture, 61% of the Leaks Were Actually Due to Endotracheal Tube Dislodgment and Only 39% Were Due to a Ruptured Cuff (Crit Care Med, 1993) [MEDLINE]
Mechanisms
  • Inadvertent Placement of the Endotracheal Tip Either Proximally (i.e. Endotracheal Tube Cuff Above the Vocal Cords) or Distally (i.e. Mainstem Bronchial Intubation)
Diagnosis
Clinical
  • Proximal Endotracheal Tube Migration
    • Decreased Peak Airway Pressure (PIP) on Ventilator
    • Hypoxemia (see Hypoxemia)
    • “Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume) (see Invasive Mechanical Ventilation-General)
    • Requirement for Increasing Volume to Maintain Endotracheal Tube Cuff Pressure: caution should be exercised in cases such as these, as unrecognized excessive inflation of the cuff may occur in the posterior oropharynx in a patient with a proximally-migrated endotracheal tube
  • Distal Endotracheal Tube Placement
    • Hypoxemia (see Hypoxemia)
    • Increased Peak Airway Pressure (PIP) on Ventilator (see Invasive Mechanical Ventilation-General)
    • Unilaterally Absent Breath Sounds (on the Non-Ventilated Side)
    • Pneumothorax (on the Overventilated Side) (see Pneumothorax): use of large tidal volume delivered unilaterally may particularly predispose to the development of pneumothorax on the ventilated side

Inadvertent Esophageal Intubation

Clinical

Inadvertent Right/Left Mainstem Bronchial Intubation

Diagnosis
  • Bronchoscopy (see Bronchoscopy): useful to rapidly identify and treat large airway mucous plugging and identify endotracheal tube tip location
  • Chest X-Ray (CXR)/Chest CT (see Chest X-Ray and Chest Computed Tomography): useful to exclude pneumothorax and diagnose atelectasis
  • Thoracic Ultrasound (see Thoracic Ultrasound): useful to exclude pneumothorax
Clinical
  • Unilaterally Absent Breath Sounds: on the non-ventilated side
  • Hypoxemia (see Hypoxemia)
  • Pneumothorax (see Pneumothorax): use of large tidal volume delivered unilaterally may particularly predispose to the development of pneumothorax on the ventilated side

Kinked Endotracheal Tube

Mechanism
  • Kinking at Endotracheal Tube Securement Device (Hollister, etc): common
  • Kinking in Posterior Oropharynx: less common
  • Kinking at Teeth (i.e. Patient Biting the Endotracheal Tube): most common site of kinking
Diagnosis
  • Bronchoscopy (see Bronchoscopy): useful to rapidly evaluate endotracheal tube patency
Clinical
  • Increased Peak Airway Pressure (PIP) on Ventilator
Prevention
  • Use of a Bite Block to Prevent Kinking of the Endotracheal Tube at the Teeth is Routinely Recommended

Post-Intubation Hemoptysis (see Hemoptysis)

Diagnosis
  • Bronchoscopy (see Bronchoscopy): useful to rapidly evaluate for a potential endotracheal/endobronchial etiology of hemoptysis
Mechanisms (Any of the Following Mechanisms May Have Increased Risk of Demonstrating Hemoptysis in the Setting of Coagulopathy)
  • Preexisting Etiology of Hemoptysis (Diffuse Alveolar Hemorrhage, etc)
  • Bronchial Wall Mucosal Injury Due to Inadvertent Mainstem Intubation
  • Laryngeal Wall Mucosal Injury
  • Oropharyngeal Trauma
  • Tracheal Wall Mucosal Injury

Post-Intubation Hypotension (see Hypotension)

Epidemiology
  • Post-Intubation Hypotension is the Most Common Complication of Intubation
  • Up to 40% of Patients Intubated in the ICU Setting Experience Significant Procedure-Related Hypoxemia or Hypotension (Crit Care, 2015) [MEDLINE]
  • Risk Factors for Post-Intubation Hypotension (Crit Care, 2015) [MEDLINE]
    • Simplified Acute Physiologic Score II (SAPS II): odds ratio 1.02 (p<0.001)
    • Age 60-75 y/o: odds ratio 1.96 (p<0.002 vs <60 y/o)
    • Age >75 y/o: odds ratio 2.81 (p<0.001 vs <60 y/o)
    • Acute Respiratory Failure as the Indication for Intubation: odds ratio 1.51 (p=0.04)
    • First Intubation in the ICU: odds ratio 1.61 (p=0.02)
    • Noninvasive Ventilation Required for Preoxygenation: odds ratio 1.54 (p=0.03)
    • Inspired FIO2 >70% After Intubation: odds ratio 1.91 (p=0.001)
Mechanisms
  • Positive-Pressure Ventilation Increases Intrathoracic and Right Atrial Pressure -> Decreases Venous Return to the Right Side of the Heart -> Decreases Right Ventricular Cardiac Output
    • This Effect is Accentuated by the Concomitant Presence of Auto-PEEP, Extrinsic PEEP, and/or Hypovolemia (Anesthesiology, 1975) [MEDLINE]
    • The Use of Pharmacologic Agents with Vasodilator Properties (Opiates, Benzodiazepines, Propofol, etc) Can Further Exacerbate this Effect
    • This Effect May Be Most Pronounced Immediately After Intubation and Initiation of Mechanical Ventilation in a Patient Who is Hypovolemic and Has Just Received Vasodilating Sedatives (Such as Midazolam, Propofol, etc) or Analgesics (Fentanyl, etc)
  • Positive-Pressure Ventilation Causes Alveolar Inflation with Compression of the Pulmonary Vascular Bed -> Increases Pulmonary Vascular Resistance (PVR) -> Decreases Right Ventricular Output (Crit Care Med, 2010) [MEDLINE]
    • Passive Leg Raise Maneuver Has Been Demonstrated to Increase Central Blood Volume and Mitigate this Effect (Crit Care Med, 2010) [MEDLINE]
  • Positive-Pressure Ventilation Causes Alveolar Inflation with Compression of the Pulmonary Vascular Bed -> Increases Pulmonary Vascular Resistance (PVR) -> Shifts the Intraventricular Septum Toward the Left (with Impaired Diastolic Left Ventricular Filling) -> Decreases Left Ventricular Cardiac Output
  • Peri-Intubation Pneumothorax (see Pneumothorax): may occur due to large tidal volume during bag-valve-mask ventilation
  • Use of Vasodilating Medications During Intubation
Interaction Between Airway Pressures and Thoracic Structures
  • Hemodynamic Effects of Positive-Pressure Mechanical Ventilation are Due to Transmission of the Airway Pressure to the Adjacent Thoracic Structures
    • Transmission is Greatest When There is Low Chest Wall Compliance (Due to Fibrothorax, etc) or High Chest Wall Compliance (Due to COPD, etc)
    • Transmission is Least When There is High Chest Wall Compliance (Due to Sternotomy, etc) or Low Lung Compliance (Due to ARDS, Pulmonary Edema, etc)
Clinical
Prevention
  • Prophylactic Intravenous Fluid/Vasopressors Prior to and/or During Endotracheal Intubation
    • Especially Indicated in Patients with Marginal Pre-Intubation Blood Pressure and/or Known Hypovolemia
  • Use of Ketamine (see Ketamine)
    • In an Analysis of Data from the Prospective, Multicenter, Observational Japanese Emergency Airway Network (JEAN-2) Study (from Feb, 2012-Nov 2017), Ketamine Manifested Less Post-Intubation Hypotension in Hemodynamically-Unstable Patients in the Emergency Department, as Compared to Midazolam or Propofol (Sci Rep, 2019) [MEDLINE]

Post-Intubation Hypoxemia (see Hypoxemia)

Epidemiology
  • Up to 40% of Patients Intubated in the ICU Setting Experience Significant Procedure-Related Hypoxemia or Hypotension (Crit Care, 2015) [MEDLINE]
Mechanisms
  • Aspiration of Oropharyngeal/Gastric Contents During Intubation (see Aspiration Pneumonia)
  • Atelectasis/Mucous Plugging (see Atelectasis): unilaterally absent breath sounds
  • Inadvertent Esophageal Intubation: bilaterally absent breath sounds
  • Inadvertent Right (or Left) Mainstem Intubation: unilaterally absent breath sounds
  • Peri-Intubation Pneumothorax (see Pneumothorax)
  • Transiently Altered V/Q Matching Due to the Introduction of Positive-Pressure Ventilation
Diagnosis
Treatment
  • Once Life-Threatening Etiologies are Promptly Excluded, Oxygenation Can Be Carefully Monitored for Improvement Over Time

Sinus Tachycardia (see Sinus Tachycardia)

Mechanisms
  • Paralysis with Inadequate Sedation: this may especially occur when a short-acting sedative (such as etomidate, etc) is utilized in conjunction with a long-acting paralytic (such as rocuronium, etc)
  • Positive-Pressure Ventilation in Hypovolemic Patient, Resulting in Decreased Venous Return to Right Side of the Heart with Decreased Cardiac Output
  • Sympathetic Nervous System Response Due to Glottic Stimulation: see below

Sympathetic Nervous System Response

Mechanisms
  • Glottic Stimulation from Laryngoscopy Blade/Endotracheal Tube (Typically in the Setting of Inadequate Sedation) Since the Glottis is Highly Innervated
  • Paralysis with Inadequate Sedation
    • May Occur Following Rapid Sequence Intubation with a Short-Acting Sedative (Such as Etomidate, etc) and a Long-Acting Paralytic (Such as Rocuronium, etc)
Clinical
  • Arrhythmias
  • Hypertension (see Hypertension)
  • Myocardial Ischemia
  • Sinus Tachycardia (see Sinus Tachycardia)
    • Note that Sinus Tachycardia May Alternatively Represent a Normal Physiologic Response to Hypovolemia Induced by Positive-Pressure Ventilation (and Decreased Venous Return to the Right Side of the Heart): it is critical to rule out hypovolemia as the etiology in this case
Prevention of Sympathetic Nervous Response Due to Glottic Stimulation
  • Sympatholytic Agent
Prevention of Hypertensive/Tachycardic Response Due to Paralysis with Inadequate Sedation
  • Ensure Adequate Sedation at All Times During Administration of Paralytic Agents

Tracheobronchial Mucosal Injury

Mechanisms
  • Tracheal Wall Mucosal Injury
  • Bronchial Wall Mucosal Injury Due to Inadvertent Mainstem Intubation
Diagnosis
  • Bronchoscopy (see Bronchoscopy)
    • Bronchoscopy is Recommended to Rapidly Determine the Site of Post-Intubation Hemoptysis (Larynx vs Tracheal Mucosal vs Endobronchial Mucosal vs Diffuse Alveolar Hemorrhage): this is especially useful in patients with pre-existing diffuse alveolar hemorrhage who only manifest hemoptysis after intubation
Clinical
  • Post-Intubation Hemoptysis (see Hemoptysis)
    • Hemoptysis May Be Significant in Patients with Coagulopathy

Vagal Response

Epidemiology
  • Laryngoscopy-Related Vagal Response is More Common in Young Patients
Mechanisms
  • Due to Laryngoscopic Stimulation
Clinical

Ventilator Circuit Leak

Diagnostic
  • Bronchoscopy (see Bronchoscopy): useful to rapidly determine the location of the endotracheal tube tip, in cases where endotracheal tube dislodgment is suspected
  • Check Endotracheal Tube and Ventilator Circuit for Disconnections or Leaks
Clinical
  • Decreased Peak Airway Pressure (PIP) on Ventilator (see Invasive Mechanical Ventilation)
  • “Lost Volume” on the Ventilator (Inspired Tidal Volume > Expired Tidal Volume)

Ventilator-Induced Lung Injury (VILI)/Barotrauma

Definitions
  • Ventilator-Induced Lung Injury (VILI): lung injury due to volume-related overstretching (“volutrauma”), high frequency of stretching, and/or high velocity/acceleration of stretching
    • VILI Likely Develops Regionally in the Lung When Low Resistance/High Compliance Lung Units Receive a Disproportionately Large Regional Tidal Volume in the Setting of High Alveolar Distending Pressures
    • Pathologically, VILI Appears as Diffuse Alveolar Damage
    • VILI is Associated with Cytokine Release and Bacterial Translocation
    • Barotrauma: clinically apparent type of alveolar injury which presents as extra-alveolar air in various locations (mediastinum, pleural space, etc)
Epidemiology
  • Mechanical Ventilation Itself Increases the Risk of Barotrauma
    • Development of Auto-PEEP During Mechanical Ventilation Further Increases the Risk of Barotrauma
    • Noninvasive Positive-Pressure Ventilation Probably Has a Similar Mechanism of Barotrauma as Invasive Mechanical Ventilation, But the Rate of Barotrauma is Lower (Due to Use of Lower Pressures) (Rev Bras Ter Intensiva, 2008) [MEDLINE]
  • Incidence of Barotrauma in ARDS is Approximately 10% (NEJM, 2000) [MEDLINE] (Intensive Care Med, 2002) [MEDLINE] (NEJM, 2004) [MEDLINE]
Physiology
  • Ventilator Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
    • Positive-Pressure Ventilation Itself
      • All Patients on Mechanical Ventilation are at Risk for Barotrauma, Since Positive-Pressure Ventilation Increases the Transalveolar Pressure (Alveolar Pressure – Adjacent Interstitial Space Pressure)
    • High Tidal Volume
      • Inappropriately High Tidal Volume Set During Bag-Valve-Mask Ventilation
      • Inappropriately High Tidal Volume Set on Ventilator (During Volume-Cycled Ventilation)
      • Inadvertent Right (or Left) Mainstem Intubation with Inappropriately High Tidal Volume Applied to a Single Lung
    • High Plateau Pressure (Pplat)
      • Plateau Pressure is the Pressure Applied to the Small Airways and Alveoli
      • While There is No Safe Plateau Pressure Under Which Barotrauma Does Not Occur, the Greatest Risk of Barotrauma Occurs with Plateau Pressure ≥35 cm H2O or Static Compliance <30 mL/cm H2O (Intensive Care Med, 2002) [MEDLINE]
    • High Peak Inspiratory Pressure (PIP)
      • There is No Absolute Safe Threshold for PIP Under Which Barotrauma Does Not Occur
      • PIP is Probably Less Associated with the Risk of Barotrauma than the Plateau Pressure, Although Some Data are Conflicting (Crit Care Med, 1983) [MEDLINE] (Chest, 1994) [MEDLINE] (Am J Respir Crit Care Med, 2002) [MEDLINE]
    • High Positive End-Expiratory Pressure (PEEP)
      • High PEEP Probably Only Contributes to an Increased Risk of Barotrauma When Open Lung Ventilation (High PEEP or Recruitment Maneuvers, Usually with Lung Protective Measure Such as Low Tidal Volume with Plateau Pressure ≤30 cm H2O) Strategies are Ineffective in Recruiting Atelectatic Lung Units in ARDS or When Lung Protective Ventilation (Low Tidal Volume with Plateau Pressure ≤30 cm H2O) is Not Utilized
    • Mode of Ventilation (Volume-Cycled vs Pressure-Cycled) Does Not Appear to Be Associated with the Risk of Barotrauma (PLoS One, 2011) [MEDLINE] (Cochrane Database Syst Rev, 2015) [MEDLINE]
  • Disease Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
    • Acute Respiratory Distress Syndrome (ARDS): due to decreased lung compliance, resulting in increased alveolar pressure (Am J Respir Crit Care Med, 1995) [MEDLINE] (Intensive Care Med, 2004) [MEDLINE]
    • Asthma (see Asthma): due to dynamic hyperinflation, resulting in increased alveolar pressure (Intensive Care Med, 2004) [MEDLINE]
    • Chronic Obstructive Pulmonary Disease (COPD) (see Chronic Obstructive Pulmonary Disease): due to dynamic hyperinflation, resulting in increased alveolar pressure
    • Interstitial Lung Disease (ILD) (see Interstitial Lung Disease): due to decreased lung compliance, resulting in increased alveolar pressure (Intensive Care Med, 2004) [MEDLINE]
    • Langerhans Cell Histiocytosis (see Langerhans Cell Histiocytosis): due to cystic lung disease, resulting in escape of air
    • Necrotizing Pneumonia (see Necrotizing Pneumonia and Pulmonary Gangrene): due to cavitating lung disease, resulting in escape of air
    • Pneumocystis Jirovecii Pneumonia (see Pneumocystis Jirovecii): due to cavitating lung disease, resulting in escape of air
  • Other Factors Which May Cause Alveolar Overdistention, Resulting in Alveolar Rupture
    • Bronchoscopy During Mechanical Ventilation: may result in prolonged increase in plateau pressure
    • High Tidal Volume During Bag-Valve-Mask Ventilation: may result in prolonged increase in plateau pressure
    • High Tidal Volume Ventilation in Pneumonectomy Patient: may result in prolonged increase in plateau pressure
    • Right Mainstem Bronchial Intubation: may result in prolonged increase in plateau pressure
    • Severe Central Airway Obstruction: may result in prolonged increase in plateau pressure
Anatomic Path of Air Dissection
  • Air from Torn Alveolus Enters the Perivascular Interstitium, Dissecting Along the Bronchovascular Sheath into the Pulmonary Hila and Subsequently Into the Mediastinum, Causing Pneumomediastinum (in the Setting of Blunt Trauma to the Lung, This Tracking of Air Has Been Termed the “Macklin Effect”) (see Pneumomediastinum) (Chest, 2001) [MEDLINE]
  • From Pneumomediastinum, Air Can Dissect Upward into the Soft Tissues of the Neck (Causing Subcutaneous Emphysema), into the Pleural Spaces (Causing Pneumothorax on Either Side), Inferiorly into the Peritoneum (Causing Pneumoperitoneum), or Rarely, into the Pericardium (Causing Pneumopericardium)
Diagnosis
  • Bronchoscopy (see Bronchoscopy): useful to rapidly identify and treat large airway mucous plugging and identify endotracheal tube tip location
  • Chest X-Ray (CXR)/Chest CT (see Chest X-Ray and Chest Computed Tomography): useful to exclude pneumothorax and diagnose atelectasis
  • Thoracic Ultrasound (see Thoracic Ultrasound): useful to exclude pneumothorax
Clinical Harbingers of Possible Barotrauma
  • Bleb (intrapleural Air Collection) (see Bullae): this represents a form of interstitial emphysema
  • Deepening of the Sulcus (Deep Sulcus Sign)
  • Hyperlucency Over the Upper Abdominal Quadrants
  • Linear Air Streaking Toward the Hilum
  • Perivascular Air Halos
  • Pneumatoceles (see Cystic-Cavitary Lung Lesions)
Clinical Manifestations
  • Pneumothorax with/without Bronchopleural Fistula (see Pneumothorax and Bronchopleural Fistula)
  • Pneumomediastinum (see Pneumomediastinum)
  • Pneumopericardium (see Pneumopericardium)
    • Epidemiology
      • Rare Manifestation of Barotrauma
  • Pneumoperitoneum (see Pneumoperitoneum)
    • Epidemiology
      • Uncommon Manifestation of Barotrauma
  • Pulmonary Interstitial Emphysema
    • Epidemiology
      • Rare Manifestation of Barotrauma: (occurs particularly with usual interstitial pneumonia from idiopathic pulmonary fibrosis) (Am J Surg Pathol, 2014) [MEDLINE]
    • Physiology
      • Air Dissects Through the Alveolar Walls into Adjacent Lung Interstitium, Causing an Inflammatory Reaction
      • Can Progress to Pneumothorax, Air Cysts within the Lung Parenchyma, and Air Embolism
  • Subcutaneous Emphysema (see Subcutaneous Emphysema)
    • Epidemiology
      • Common Manifestation of Barotrauma
  • Subpleural Air Cyst
    • Epidemiology
      • Uncommon Manifestation of Barotrauma
  • Tension Lung Cyst
    • Epidemiology
      • Uncommon Manifestation of Barotrauma
  • Venous Air Embolism (see Air Embolism) (Am Rev Respir Dis, 1993) [MEDLINE]
    • Epidemiology
      • Uncommon Manifestation of Barotrauma
Prevention
  • General Comments: while both barotrauma and volutrauma likely contribute to alveolar injury, limiting alveolar pressure appears to be the most effective measure to prevent barotrauma
  • Avoid Dynamic Hyperinflation (in Asthma and COPD): hyperinflation is progressive (dynamic) since air accumulates in the lung with each breath as a result of a failure to achieve complete exhalation before the onset of the next breath
    • Treatment of Bronchospasm (see Obstructive Lung Disease): usually with bronchodilators, corticosteroids, etc
    • Use Low Tidal Volume Ventilation: reduces amount of air in each breath which needs to be exhaled
    • Use Short Inspiratory Time/Longer Expiratory Time: allows adequate time for expiration
    • Use Lower Respiratory Rate (Even Using Permissive Hypercapnia in Some Cases)
  • Maintain Low Plateau Pressure (Pplat ≤30 cm H2O): being cautious to avoid Pplat >35 cm H2O
    • Targeting Even Lower Plateau Pressures May Further Reduce the Risk of Barotrauma (Am J Respir Crit Care Med, 1999) [MEDLINE]
  • Maintain Low Tidal Volume Ventilation (6 mL/kg Predicted Body Weight) (N Engl J Med, 2000) [MEDLINE]
  • Neuromuscular Blockade
    • In in Systematic Review and Meta-Analysis, Use of Neuromuscular Blockade is Associated with a Decreased Risk of Barotrauma (Crit Care, 2013) [MEDLINE]
  • Use Appropriate Amounts of PEEP
    • PEEP is Standardly Titrated Per the FIO2/PEEP Table as was Used in the 2000 Study on Low Tidal Volume Ventilation (N Engl J Med, 2000) [MEDLINE]
  • Use Low Respiratory Rate: even using permissive hypercapnia in some cases
Management-General
  • Since the Occurrence of Any Barotrauma in the Setting of Mechanical Ventilation for ARDS Suggests Either a Patient with More Severe ARDS (at Higher Mortality Risk) or a Suboptimal Ventilation Strategy (or Both), the First Priority Should Be Measures to Optimize the Ventilation Management
    • Use Lung Protective/Low Tidal Volume Ventilation (Ideally to 6 mL/kg PBW) and Adjust the Respiratory Rate to the Minimum Required to Maintain an Adequate pH (i.e. Permissive Hypercapnia)
      • Use Sedation and Pharmacologic Paralysis as Necessary to Maintain Ventilator Parameters
    • Avoid Patient-Ventilator Dyssynchrony and Overbreathing
      • Use Sedation and Pharmacologic Paralysis as Necessary to Maintain Synchrony
    • Decrease Both the Auto-PEEP and Extrinsic PEEP (As Allowed by Oxygenation)
      • Target a Low I/E Ratio (Around 0.33) to Maintain a Low Mean Airway Pressure
      • Shorten Inspiratory Time with Higher Inspiratory Flow Rate (Around 70-100 L/min)
      • Lengthen Expiratory Time
      • Avoid Inverse Ratio Ventilation
      • Use a Low Compressible Volume (Non-Disposable) Ventilator Circuit
    • Treat Bronchospasm
    • Treat Underlying Etiology of Respiratory Failure to Minimize the Total Duration of Mechanical Ventilation
Management-Pneumothorax (see Pneumothorax)
  • Chest Tube (see Chest Tube)
    • Chest Tube is Generally Required for Mechanical Ventilation-Associated Pneumothorax, Since >30% of These Progress to Tension Pneumothorax
Management-Chest Tube with Air Leak (i.e. Bronchopleural/Alveolopleural Fistula) (see Bronchopleural Fistula): ventilator changes should aim to decrease the plateau pressure (to Pplat ≤30 cm H2O)
  • Optimization of Ventilation Management: as above
  • Continue Chest Tube Drainage (see Chest Tube): while this may seem obvious, prematurely removing a chest tube in a patient with an air leak from a bronchopleural fistula can result in the rapid development of tension pneumothorax (which can be potentially fatal)
  • Use the Least Amount of Chest Tube Suction Which Maintains Lung Inflation and Decreases the Amount of Air Leak
  • Optimize Body Position and Patient’s Sedation/Pharmacologic Paralysis to Minimize the Air Leak
  • Other Less Established Techniques
Management-Pneumomediastinum (see Pneumomediastinum)
  • Optimization of Ventilation Management: as above
  • Rare Cases of Tension Pneumomediastinum May Require Mediastinotomy For Decompression
Management-Pneumopericardium (see Pneumopericardium)
  • Optimization of Ventilation Management: as above
  • Rare Cases with Tamponade May Require Pericardiocentesis with Drain Placement for Decompression
Management-Pneumoperitoneum (see Pneumoperitoneum)
  • Optimization of Ventilation Management: as above
  • Barotrauma-Associated Pneumoperitoneum is Usually Self-Limited and Doesn’t Require Specific Intervention (Other than Ventilator Adjustments, Such as a Decrease in Plateau Pressure, etc)
  • Rare Cases of Pneumoperitoneum-Associated Abdominal Compartment Syndrome May Require Lapartotomy/Laparoscopy for Surgical Decompression (to Both Relieve the Compartment Syndrome and to Exclude a Perforated Viscus)
Management-Pulmonary Interstitial Emphysema
  • Optimization of Ventilation Management: as above
  • Treat Underlying Etiology
Management-Subcutaneous Emphysema (see Subcutaneous Emphysema)
  • Optimization of Ventilation Management: as above
  • Manage Underlying Pneumothorax (If Present) (see Pneumothorax): as above
  • Blowhole Incision (see Blowhole Incision)
Management-Venous Air Embolism (see Air Embolism)
  • Optimization of Ventilation Management: as above
  • Standard Management
Prognosis
  • In Mixed Populations, Mechanical Ventilation-Associated Barotrauma is Associated with an Increased Mortality Rate (Chest, 1986) [MEDLINE]
  • ARDS-Associated Barotrauma is Associated with an Increased Mortality Rate: likely related to the fact that the barotrauma is a marker for patients with worse ARDS (Crit Care Med, 1995) [MEDLINE] (JAMA, 1994) [MEDLINE]

Early Adverse Effects/Complications (Manifest Within Hours-Weeks After Intubation)

Acute Kidney Injury (AKI) (see Acute Kidney Injury)

Epidemiology
  • Mechanical Ventilation is Associated with an Increased Risk of Acute Kidney Injury
    • BEST Kidney Trial (JAMA, 2005) [MEDLINE]: n = 29,269 critically ill patients
      • Positive-Pressure Mechanical Ventilation was an Independent Risk Factor for Acute Kidney Injury (Odds Ratio 2.11, 95% CI: 1.58-2.82)
Mechanism
  • May Be Related to Increased Release of Inflammatory Mediators (Such as IL-6), Impaired Renal Perfusion Associated with Decreased Cardiac Output, Increased Sympathetic Tone, and/or Humoral Pathway Activation (Crit Care Med, 2005) [MEDLINE]

Arytenoid Cartilage Dislocation (see Arytenoid Cartilage Dislocation)

Epidemiology
  • Arytenoid Cartilage Dislocation Has Been Reported as a Rare Complication of Intubation (Br J Anaesth, 1978) [MEDLINE]
  • Risk Factors for Arytenoid Cartilage Dislocation/Subluxation (Ann Card Anaesth, 2017) [MEDLINE]: Japanese retrospective review of 19,437 adult patients
    • Cardiovascular Surgery (Odds Ratio: 9.9, p<0.001)
    • Difficult Intubation (Odds Ratio: 12.1, p=0.018)
  • Body Mass Index (BMI) is a Risk Factor for Arytenoid Cartilage Dislocation ( J Voice, 2018) [MEDLINE]
Mechanisms
  • Laryngoscopic Trauma to Arytenoids
Clinical
  • Hoarseness (see Hoarseness): typically manifests only after the patient is extubated

Aspiration Pneumonia (see Aspiration Pneumonia)

Epidemiology
  • Aspiration of Oropharyngeal Secretions is Common with Endotracheal Tubes and Tracheostomy Tubes
  • Presence of Gag Reflex Does Not Confer Protection Against Aspiration with Endotracheal Intubation or Tracheostomy (Crit Care Med, 1990) [MEDLINE]
  • Polyurethane Endotracheal Tube Cuffs Decrease the Amount of Leakage Around the Cuff, as Compared to Polyvinyl Chloride Cuff Endotracheal Tubes (Crit Care Med, 2008) [MEDLINE]
Mechanisms
  • Delayed Triggering of the Swallowing Response (Crit Care Med, 1990) [MEDLINE]
  • Pharyngeal Pooling of Secretions Above the Airway Cuff (Crit Care Med, 1990) [MEDLINE]
    • Risk of Aspiration is Correlated with the Amount of Oropharyngeal Secretions

Auto-Positive End-Expiratory Airway Pressure (Auto-PEEP or Intrinsic PEEP) (see Invasive Mechanical Ventilation-General) (Am Rev Respir Dis, 1982) [MEDLINE]

  • See Above

Cervical Spinal Cord Injury (SCI) (see Spinal Cord Injury)

Mechanisms

Dental/Lingual/Orolabial or Pharyngeal Mucosal Damage

  • See Above

Endotracheal Tube Tip Malpositioning

  • See Above

Esophageal Injury/Perforation

Mechanisms
  • Trauma Due to Inadvertent Esophageal Intubation
    • Trauma May Result from Either the Endotracheal Tube Stylet or the Endotracheal Tube Itself
Clinical

Gastrointestinal Complications

Acalculous Cholecystitis (see Acalculous Cholecystitis)
  • Epidemiology
    • Acalculous Cholecystitis Has Been Reported on Occur in 0.2-3% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Constipation
  • Epidemiology
    • Constipation Has Been Reported on Occur in 15% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Diarrhea (see Diarrhea)
  • Epidemiology
    • Diarrhea Has Been Reported on Occur in 15-51% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
  • Mechanisms
    • Tube Feedings (Related to Hyperosmolar Tube Feedings, High Infusion Rate, and/or Dietary Lipids)
    • Clostridium Difficile Infection (see Clostridium Difficile)
    • Medications (Such as Antibiotics, Magnesium-Based Antacids, H2-Receptor Antagonists)
    • Hypoalbuminemia (Especially Chronic Severe Hypoalbuminemia <2.6 g/dL)
    • Prolonged Fasting >5 Days: interferes with bile acid homeostasis, due to intestinal mucosal atrophy
Erosive Esophagitis (see Esophagitis)
  • Epidemiology
    • Erosive Esophagitis Has Been Reported to Occur in 48% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
Gastrointestinal Stress Ulceration (see Peptic Ulcer Disease)
  • Epidemiology
    • Stress-Related Mucosal Damage is the Most Common Etiology of Gastrointestinal Hemorrhage in Mechanically-Ventilated Patients
    • Endoscopically-Identified But Asymptomatic Stress Ulceration Has Been Reported to Occur in 74-100% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
    • Clinically Evident Gastrointestinal Hemorrhage Due to Stress Ulceration Has Been Reported to Occur in 5-25% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
    • Clinically Significant Gastrointestinal Hemorrhage Due to Stress Ulceration Has Been Reported to Occur in 3-4% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
  • Mechanisms
    • Positive-Pressure Mechanical Ventilation is Associated with Decreased Splanchnic Perfusion, Possibly Related to Decreased Cardiac Output (Intensive Care Med, 2000) [MEDLINE] (Intensive Care Med, 2000) [MEDLINE]: decreased splanchnic perfusion results in increased levels of aminotransferases and lactate dehydrogenase (LDH)
  • Clinical
    • Mucosal Lesions Tend to Be Multiple and Occur Predominantly in the Fundus of the Stomach (Typically Sparing the Antrum)
    • Distal (Antral and Duodenal) Mucosal Erosions and/or Ulcers May Also Occur
      • Distal (Antral and Duodenal) Mucosal Erosions Tend to Appear Later
      • Distal (Antral and Duodenal) Mucosal Erosions Tend to Be Deeper
      • Distal (Antral and Duodenal) Mucosal Erosions May Be Associated with a Higher Incidence of Gastrointestinal Hemorrhage
Ileus (and Gastrointestinal Hypomotility) (see Ileus)
  • Epidemiology
    • Decreased Bowel Sounds Have Been Reported on Occur in 50% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
    • High Gastric Residuals Have Been Reported to Occur in 39% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
    • Ileus Has Been Reported to Occur in 4-10% of Mechanically-Ventilated Patients (Chest, 2001) [MEDLINE]
  • Mechanisms
    • Gastrointestinal Dysmotility Has Been Demonstrated in Mechanically-Ventilated Patients (Crit Care Med, 1994) [MEDLINE]
  • Clinical
    • Hypomotility with Tube Feeding Intolerance/Ileus
  • Management
    • Avoid Medications Which Impair Gastrointestinal Motility

Hypoxic-Ischemic Brain Injury (see Hypoxic-Ischemic Brain Injury)

Mechanisms
  • Prolonged Hypoxia During Attempted Intubation

Impaired Mucociliary Motility

Physiology
  • Positive-Pressure Mechanical Ventilation Impairs Airway Mucociliary Clearance, Increasing the Risk of Secretion Retention and Pneumonia (Chest, 1994) [MEDLINE]
Management
  • Nebulized N-Acetylcysteine (Mucomyst) (see N-Acetylcysteine)
    • Randomized Trial of Routine vs On-Demand Nebulized N-Acetylcysteine with Salbutamol in Mechanically-Ventilated Patients (≥24hrs) in the ICU (JAMA, 2018) [MEDLINE]: n = 922
      • Routine Nebulized N-Acetylcysteine with Salbutamol Did Not Decrease the Number of Ventilator-Free Days, as Compared to On-Demand Nebulized N-Acetylcysteine with Salbutamol
      • There was No Difference in Length of Stay, Mortality, or the Proportion of Patients Developing Pulmonary Complications Between the Groups
      • Routine Nebulized N-Acetylcysteine Increased the Risk of Tachyarrhythmias and Agitation

Intensive Care Unit-Acquired Weakness (see Intensive Care Unit-Acquired Weakness)

Epidemiology
  • Weakness is Common in Mechanically-Ventilated Patients (Chest, 2007) [MEDLINE]
    • However, it is Unclear as to Whether Mechanical Ventilation Itself Independently Causes Weakness
Mechanisms
Management
  • Early Physical Therapy/Mobilization
    • Randomized Trial of Early Mobilization in Mechanically-Ventilated Patients (Lancet, 2009) [MEDLINE]
      • Early Mobilization within 72 hrs of Intubation was Safe, Well-Tolerated, and Associated with Improved Functional Outcomes at Hospital Discharge, Shorter Duration of Delirium, and More Ventilator-Free Days, as Compared to Standard Care
Recommendations (Related to Early Mobilization) (Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU) (Crit Care Med, 2018) [MEDLINE]
  • Assuming Stability of the Following Parameters, Rehabilitation or Mobilization is Recommended in Critically Ill Adults (Conditional Recommendation, Low Quality Evidence)
    • Cardiovascular Stability Criteria
      • Heart Rate 60-130 bpm
      • Systolic Blood Pressure 90-180 mm Hg (or Mean Arterial Pressure 60-100 mm Hg)
      • Absence of New/Symptomatic Arrhythmia
      • Absence of Chest Pain Due to Myocardial Ischemia
    • Respiratory Stability Criteria
      • Respiratory Rate 5-40 breaths/min
      • SpO2 ≥88%
      • FiO2 <60% and Positive End-Expiratory Pressure <10 cm H2O
      • Endotracheal Tube/Tracheostomy is Adequately Secured
    • Neurologic Stability Criteria
      • Able to Open Eyes to Voice
      • Absence of Unstable Spinal Injury/Lesion
    • Other Stability Criteria
      • Absence of Unstable Fracture and Active/Uncontrolled Gastrointestinal Hemorrhage
      • Mobilization May Be Performed with Femoral Vascular Access Devices (Except Femoral Sheaths in Which Hip Mobilization is Generally Avoided), Continuous Renal Replacement Therapy, and Infusion of Vasoactive Medications
  • Serious Safety Events or Harms are Uncommon During Physical Rehabilitation/Early Mobilization (Ungraded Statement)
  • Indicators for Stopping Physical Rehabilitation/Early Mobilization Include the Development of New Cardiovascular, Respiratory, or Neurologic Instability (Ungraded Statement)
    • Cardiovascular Instability
      • Deviation from Above Stability Criteria
    • Pulmonary Instability
      • Deviation from Above Stability Criteria
      • Ventilator Dyssynchrony
    • Neurologic Instability
      • Change in Level of Consciousness (Not Following Directions, Lightheadedness, Combative Behavior, or Agitation)
    • Other Instability
      • Fall
      • Hemorrhage
      • Medical Device Removal or Malfunction
      • Patient Distress

Laryngeal Injury

Epidemiology
  • Endotracheal Tube-Associated Laryngeal Injury is the Most Common Complication Associated with Endotracheal Tube Placement
    • Laryngeal Edema/Inflammation is Observed Post-Extubation in >50% of Intubations (Chest, 1989) [MEDLINE] and (Intensive Care Med, 2010) [MEDLINE]
      • However, Not All Cases are Significantly Symptomatic
    • Clinically Significant Laryngeal Edema Occurs in 5-13% of Extubated Patients, But Only 1% Require Reintubation (Anesthesiology, 1992) [MEDLINE]
    • Fiberoptic Study of Endotracheal Intubation-Associated Laryngeal Injuries (Intensive Care Med, 2010) [MEDLINE]: prospective study of n = 136 patients extubated after >24 hrs of mechanical ventilation (median duration of intubation = 3 days)
      • Approximately 73% of Patients Demonstrated a Laryngeal Injury
      • The Most Common Lesions were Edema (67% of Cases) and Abnormal Vocal Mobility (67% of Cases)
    • Incidence of Postextubation Stridor Has Been Reported to Be Between 6-37% (J Evid Based Med, 2011) [MEDLINE]
  • Sex
    • Laryngeal Injuries are More Common in Females than Males (Anesthesiology, 1992) [MEDLINE]
  • Obesity
    • Obesity Does Not Appear to Increase the Risk of Laryngeal Injury, Although it Increases the Risk for Difficult Intubation (Intern Emerg Med, 2013) [MEDLINE]
  • Risk Factors Associated with Endotracheal Tube-Associated Laryngeal Injury (Otolaryngol Head Neck Surg, 1994) [MEDLINE] and (Intensive Care Med, 2010) [MEDLINE]
  • Risk Factors Not Associated with the Severity of Endotracheal Tube-Associated Laryngeal Injury (Laryngoscope, 2011) [MEDLINE]
    • Duration of Intubation
    • Endotracheal Tube Size: including use of endotracheal tubes with subglottic suction ports
Mechanisms
  • Trauma Due to the Laryngoscopy Blade, Endotracheal Tube Stylet, or the Endotracheal Tube During Intubation
  • Direct Endotracheal Tube Pressure on the Larynx and Surrounding Tissues (with//without Associated Inflammation)
Diagnosis
Clinical
Treatment
  • Generally Resolves within 24-48 hrs After Extubation
  • Racemic Epinephrine (see Epinephrine)
  • HELIOX (see Heliox)
  • Corticosteroids (see Corticosteroids)
  • Reintubation: may be required

Neurologic Complications

Cervical Spinal Cord Injury (SCI) (see Spinal Cord Injury)
Hypoxic-Ischemic Brain Injury (see Hypoxic-Ischemic Brain Injury)
  • Mechanisms
    • Prolonged Hypoxia During Attempted Intubation
Increased Intracranial Pressure (ICP) (see Increased Intracranial Pressure)
  • Mechanism
    • Positive-Pressure Mechanical Ventilation Increases Intracranial Pressure (Likely Mediated by Impairment of Cerebral Venous Outflow)
Neuronal Damage
  • Mechanism
    • Positive-Pressure Mechanical Ventilation Has Been Demonstrated to Cause Hippocampal Apoptosis in Animal Studies (Am J Respir Crit Care Med, 2013) [MEDLINE]
    • Hippocampal Changes May Be Related to the Development of Delirium

Oxygen Toxicity (see Oxygen)

Epidemiology
  • Prior Exposure to Bleomycin Increases the Risk of Toxicity from Hyperoxia (Am Rev Respir Dis. 1984) [MEDLINE] (see Bleomycin)
Physiology
  • Mechanisms by Which Hyperoxia Contributes to the Development of Lung Injury
    • Absorptive Atelectasis
      • High FIO2 Causes a Washout of Alveolar Nitrogen and Replacement by Oxygen, Resulting in Absorption of Alveolar Oxygen into the Blood
    • Formation of Reactive Oxygen Intermediates (Such as Superoxide Anion, Hydroxyl Radical, and Hydrogen Peroxide) Which Overwhelm the Cell’s Antioxidant Defense Mechanisms
      • Concentration of Reactive Oxygen Intermediates In Exhaled Gas Increases After Only 1 hr of Breathing 28% FIO2, Regardless of the Presence of Lung Disease (Thorax, 2004) [MEDLINE]
      • Reactive Oxygen Intermediates React with Various Intracellular Macromolecules (Impairing Their Function), Resulting in Cell Death
    • Impairment of Bactericidal Function of Immune Cells, Resulting in an Increased Risk of Infection
    • Impairment of Mucociliary Clearance, Resulting in an Increased Risk of Infection
    • Increased Susceptibility to Mucous Plugging
    • Induction of a Deleterious Inflammatory Response, Resulting in Secondary Apoptosis and Tissue Damage
  • Volunteer Studies Breathing FIO2 100% x 6-48 hrs Variably Induced Tracheobronchitis, Substernal Burning, Chest Tightness, and a Dry Cough
  • Tolerance of Hyperoxia Appears to Be Related to an Ability to Generate Antioxidants: this tolerance may be genetically determined
  • Phases of Oxygen Toxicity (Phases Overlap)
    • Acute/Exudative Phase: usually begins within 48-72 hrs, depending on inspired oxygen fraction (and is believed to be reversible)
      • Perivascular, Interstitial, and Alveolar Edema -> atelectasis and alveolar hemorrhage
    • Subacute/Proliferative Phase: usually begins after 4th-7th day (and is believed to be irreversible)
      • Rebsorption of Exudates
      • Hyperplasia of Type II Pneumocytes
      • Deposition of Collagen and Elastin in Interstitium and Hyaline Membrane Deposition
Clinical
Treatment
  • Preventive Measures: maintain pO2 <80 mmHg and FIO2 <40-50%

Patient-Ventilator Dyssynchrony

Definition
  • Delivery of Breath from the Ventilator Which is Not Matched by the Patient Effort
Epidemiology
  • More than 10% of Breaths were Found to Be Dyssynchronous in 24% of Mechanically-Ventilated Patients in One Observational Study (Intensive Care Med, 2006) [MEDLINE]
    • Ineffective Triggering and Double-Triggering were the Most Commonly Observed Events
    • Dyssynchrony Occurred in Both Assist Control and Pressure Support Ventilation Modes
    • Dyssynchrony was Associated with a Prolonged Duration of Mechanical Ventilation (7.5 days, IQR 3-20 vs 25.5, IQR 9.5-42.5)
Mechanisms
  • Ventilator Breath Triggering Problem
    • General Comments
      • Triggering Dyssynchronies are the Best Studied of All Forms of Dyssynchrony
      • Triggering Dyssynchronies Occur in 26-82% of All Mechanically-Ventilated Patients (Am J Respir Crit Care Med, 2001) [MEDLINE] ( J Crit Care, 2009) [MEDLINE] (Crit Care Med, 2009) [MEDLINE]
      • Triggering Dyssynchronies Occur More Commonly in Patients with COPD and Obstructive Lung Diseases (Intensive Care Med, 2012) [MEDLINE]: this can be overcome
    • Ineffective Triggering
      • Ventilator Triggering Has an Inherent Delay (Up to 100 msec or More)
      • Etiologies of Ineffective Triggering (Intensive Care Med, 2006) [MEDLINE]
        • Insensitive Inspiratory (Pressure or Flow) Trigger
        • Higher Level of Pressure Support
        • Higher Tidal Volume
        • Higher pH
      • Ventilator Triggering Sensitivity is Generally Set High Enough to Avoid to Inadvertent “Auto-Triggering” (Due to Cardiac Oscillations, etc)
    • Excessive Triggering
      • Etiologies of Excessive Triggering
        • Excessively Sensitive Inspiratory (Pressure or Flow) Trigger
        • Hiccups (see Hiccups)
      • Types of Excessive Triggering
        • Auto-Triggering
        • Breath-Stacking (When a Second Breath is Delivered Before the First Breath Has Completed)
        • Entrainment (When Ventilator-Delivered Gas Flow Elicits an Effort During the Breath)
    • Effect of Auto-PEEP on Triggering
      • In the Setting of Auto-PEEP, Triggering Requires the Patient to First Overcome the End-Expiratory Positive Pressure (This Represents an Inspiratory Load for the Patient, Increasing the Work of Breathing)
    • Cardiogenic Auto-Triggering Dyssynchrony
      • Cardiac Systole Can Result in Several Milliliters of Airflow (Which are Correlated with Changes in Intrathoracic Pressure) (Respir Physiol, 1996) [MEDLINE]
      • Cardiogenic Auto-Triggering May Therefore Occur in Some Cases
      • Cardiogenic Auto-Triggering Has Been Described in the Setting of Brain Death, Hyperdynamic Hemodynamic State, Post-Cardiac Surgery, and Hemoperitoneum (Chest, 2020) [MEDLINE]
    • Reverse Triggering Dyssynchrony
      • Reverse Triggering Dyssynchrony was First Described in 2013 (Chest, 2013) [MEDLINE]
      • Reverse Triggering Dyssynchrony May Occur in Up to 30% of Patients with ARDS (Intensive Care Med, 2019) [MEDLINE]
      • The Mechanism of Reverse Triggering is Unclear
      • Reverse Triggering May Be Observed During Deep Sedation, During Transition from Sedation to an Awakened State, or Even in a Brain Dead Patient (Am J Respir Crit Care Med, 2016) [MEDLINE]
      • Reverse Triggering Dyssynchrony is Manifested by a Ventilator-Delivered Breath Paradoxically Triggering a Diaphragmatic Contraction, Which then Initiates a Spontaneous Breath, Resulting in Breath Stacking (Chest, 2013) [MEDLINE]
      • Reverse Triggering Dyssynchrony Causes Overdistention, Increases the Work of Breathing, and May Cause Diaphragmatic Muscle Damage
      • Deepening of the Sedation Paradoxically Increases the Incidence of Reverse Triggering Dyssynchrony: this is critical, since deep sedation may be employed to prevent or manage ventilator dyssynchrony (thereby, inadvertently increasing the risk of reverse triggering dyssynchrony)
  • Ventilator-Delivered Flow Pattern Problem
    • During an Interactive Breath, Inspiratory Muscles are Contracting with the Ventilator Delivering Flow Which Should Be Adequate to Provide Muscle Unloading, Achieving Flow Synchrony
    • Flow Dyssynchrony Can Occur and Manifests as a Tachypneic, Dyspneic Patient (“Flow Starvation”) and Abnormality in the Pressure Waveform on the Ventilator (Pressure Waveform is “Sucked Downward”, Often Below the Baseline)
  • Breath Cycling Problem
    • Cycling Dyssynchronies Probably Occur in <10% of Mechanically-Ventilated Patients
    • Two Mechanisms
      • Ventilator-Delivered Breath Extends Beyond the Duration of the Patient Effort, Resulting in Shortened Expiratory Time (with Gas Trapping)
      • Ventilator-Delivered Breath Ends Before the Patient Effort Has Finished (“Breath Stacking”), Resulting in an Increased Inspiratory Load
Diagnosis
  • Patient-Ventilator Dyssynchrony Can Be Diagnosed Using Observation of the Patient Respiratory Effort and the Ventilator Waveforms (Respir Care, 2005) [MEDLINE]
    • The Most Readily Apparent Type of Dyssynchrony is the Failure of the Ventilator to Trigger a Breath with a Patient Effort
  • Reverse Triggering is Difficult to Detect without the Use of an Esophageal Balloon or Diaphragmatic Electromyogram (EMG)
Clinical
  • “Breath Stacking” (Patient Triggers the Next Breath Before the Last Breath is Completed)
    • Breath Stacking was Commonly Observed in Low Tidal Volume Mechanical Ventilation for ARDS (Crit Care Med, 2008) [MEDLINE]
  • Dyspnea (see Dyspnea) (Respir Care, 2000) [MEDLINE]
  • Increased Work of Breathing (Intensive Care Med, 2006) [MEDLINE]
  • Prolonged Duration of Mechanical Ventilation (Intensive Care Med, 2006) [MEDLINE] (Crit Care Med, 2009) [MEDLINE]
  • Increased Sedative Use in Mechanically-Ventilated Patients
  • Increased ICU Length of Stay (Crit Care Med, 2009) [MEDLINE]
  • Increased ICU and Hospital Mortality (Intensive Care Med, 2015) [MEDLINE]
Management
  • Set Ventilator Triggering Sensitivity to a Setting as Low as Possible without Inducing Auto-Triggering
    • If Double-Triggering is Occurring, Decrease the Trigger Sensitivity (e.g. from -1 to -3 cm H2O)
  • Treat Auto-PEEP (If Present): prolong the expiratory time, decrease tidal volume, decrease respiratory rate, bronchodilators, etc
  • Avoid Modes Which Deliver Multiple Different Breath Types (SIMV, etc)
  • Adjust Flow Magnitude and Profile (Sine, Square, Decelerating), If Flow-Targeted Breaths are Desired
    • Increasing the Flow Rate When Increasing the Tidal Volume Will Ensure that the Inspiratory Time Remains Constant (Am J Respir Crit Care Med, 1995) [MEDLINE]
  • Set Breath Duration Using the Cycle Variable (Volume, Time, Flow) to Optimize Comfort
  • Proportional Assist Ventilation (PAV): may be useful
  • Neurally-Adjusted Ventilatory Assistance (NAVA): may be useful

Pharyngitis (see Pharyngitis)

Epidemiology
  • Common
    • Pharyngitis is Common and Occurs in Anywhere from 14-57% of Patients Intubated for Operative General Anesthesia (J Clin Anesth, 2010) [MEDLINE] (J Int Med Res, 2017) [MEDLINE]
  • Risk Factors for Postoperative Endotracheal Intubation-Associated Pharyngitis
    • Cough During Emergence from General Anesthesia (J Int Med Res, 2017) [MEDLINE]
    • Female Sex (Br J Anaesth, 2002) [MEDLINE]
    • Greater Area of Endotracheal Tube Contact with the Tracheal Mucosa (Anesthesiology, 1983) [MEDLINE]
    • Higher Endotracheal Tube Cuff Pressure (J Int Med Res, 2017) [MEDLINE]
    • Large Endotracheal Tube (Anesthesiology, 1987) [MEDLINE] (Acta Anaesthesiol Scand, 2010) [MEDLINE]
    • Use of Nasogastric Tube During Surgery
Mechanisms
  • Mild Trauma to Upper Airway Mucosa
Clinical
  • Sore Throat
Prevention
  • Preoperative Use of Magnesium Lozenges
  • Preoperative Use of Zinc Lozenges (Anesth Analg. 2018) [MEDLINE]
    • Note: Topical Lidocaine Applied to Upper Airway Structures or the Endotracheal Tube May Actually Increase the Risk of Postoperative Pharyngitis Due to the Endotracheal Tube (Can Anaesth Soc J, 1980) [MEDLINE] (Acta Anaesthesiol Scand, 1992) [MEDLINE]
  • Use of Conical-Shaped Endotracheal Tube Cuff (As Compared to Cylindrical-Shaped Cuff) (Anesth Analg, 2017) [MEDLINE]
  • Use the Lowest Effective Endotracheal Tube Cuff Pressure: generally <20 mm Hg
    • Use of Nitrous Oxide During Surgery Results in the Nitrous Oxide Diffusing into the Endotracheal Tube Cuff (and Undesirably Increasing the Endotracheal Tube Cuff Pressure)
    • Head Down Positioning During Surgery Increases the Endotracheal Tube Cuff Pressure
  • Use the Appropriate Endotracheal Tube Size (for Patient Sex and Size)
    • Female: 7-7.5 mm (internal diameter), which may require adjustment for patient size
    • Male: 7.5-8 mm (internal diameter), which may require adjustment for patient size
Treatment
  • Usually Self-Limited: lasting <48 hrs (Acta Anaesthesiol Scand, 2010) [MEDLINE]
    • In Cases with Persistent or Severe Hoarseness/Dysphagia, Otolaryngologic Evaluation May Be Warranted to Evaluate for Specific Intubation-Associated Injury

Positive Pressure-Induced Artifacts Introduced into the Measurement of Hemodynamic Pressures

Mechanism
  • Airway Pressure Transmission to Thoracic Structures, Resulting in Artifactual Elevation of Hemodynamic Pressure Measurements: this occurs because (by convention) most hemodynamic pressures are assessed at end-expiration (when PEEP is the predominant determinant of airway pressure)
Clinical
  • PEEP Artifactually Elevates the Pulmonary Capillary Wedge Pressure (PCWP) (see Hemodynamics)
    • Correction of PEEP Consists of Subtracting Approximately One Half of the PEEP Level from the PCWP if the Lung Compliance is Normal (or One Quarter of the PEEP Level if the Lung Compliance is Decreased) (J Appl Physiol Respir Environ Exerc Physiol, 1982) [MEDLINE]
    • Correction of the PCWP for the Amount of PEEP Can More Accurately Done Using the Index of Transmission (Crit Care Med, 2000) [MEDLINE]
      • Index of Transmission = (End Inspiratory PCWP – End Expiratory PCWP) / (Plateau Pressure – Total PEEP)
      • Transmural PCWP = End-Expiratory PCWP – (Index of Transmission x Total PEEP)
      • This Estimation Can Be Unreliable if the Respiratory Variation of the PCWP is Greater than that of the Pulmonary Arterial Pressure Tracing
  • PEEP May Also Artifactually Elevate the Central Venous Pressure (CVP) (see Hemodynamics)

Sleep Disruption

Epidemiology
  • Sleep Disruption is Common in Mechanically-Ventilated Patients (Chest, 2000) [MEDLINE]
Mechanisms (Am J Respir Crit Care Med, 2003) [MEDLINE]
  • Patient-Related Factors (Anxiety, Fear, Hospital Attire, Disorientation, Lack of Privacy, Loneliness, Lack of Familiarity with Staff, Lack of Understanding of Medical Terms, etc)
  • Environment-Related Factors (Noise, Light, Comfort of Bed, Disrupted Circadian Rhythms, Visitors, Room Ventilation, Bad Odor, Hand Washing by Providers, etc)
  • Disease-Related Factors (Pain, Dyspnea, Coughing, Thirst, Nausea, Need to Use Bedpan/Urinal, etc)
  • Treatment-Related Factors (Nursing Care, Patient Procedures, Vital Sign Measurement, Medication Administration, Oxygen Mask, Endotracheal Tube, Urinary Catheter, Mode of Mechanical Ventilation, etc)
    • Specific Ventilator Modes Might Contribute Differentially to Sleep Disruption (Am J Respir Crit Care Med, 2002) [MEDLINE] (Crit Care Med, 2008) [MEDLINE]
Diagnosis
  • Identification of Sleep in Critically Ill Patients is Difficult with Standard Criteria (Sleep Med, 2012) [MEDLINE]
General Management
  • Sound Reduction Strategies May Be Useful to Improve Sleep in ICU Patients (Crit Care, 2013) [MEDLINE]
  • Pressure Support Ventilation Should Be Avoided in Patients with Central Sleep Apnea (Especially Those with Congestive Heart Failure and Chronic Respiratory Failure) (Intensive Care Med, 2016) [MEDLINE]
Recommendations (Society of Critical Care Medicine Clinical Practice Guidelines for the Prevention and Management of Pain, Agitation/Sedation, Delirium, Immobility, and Sleep Disruption in Adult Patients in the ICU) (Crit Care Med, 2018) [MEDLINE]
  • Features of Sleep in the Critically Ill Patient (Ungraded Statement)
    • Total Sleep Time (TST) and Sleep Efficiency are Often Normal
    • Sleep Fragmentation, the Proportion of Time Spent in Light Sleep (Stages N1 + N2), and Time Spent Sleeping During the Day (vs Night) are Higher
    • The proportion of Time Spent in Deep Sleep (Stage N3 Sleep and REM) is Lower
    • Subjective Sleep Quality is Decreased
  • Influence of Delirium on Sleep (Ungraded Statement)
    • The Presence of Delirium May Not Affect Total Sleep Time, Sleep Efficiency, or Sleep Fragmentation
    • The Influence of Delirium on the Proportion of Time Spent in Light (N1 + N2) vs Deeper (N3) Sleep is Unknown
    • The Presence of Delirium Decreases REM Sleep
    • Delirium is Associated with Greater Circadian Sleep-Cycle Disruption and Increased Daytime Sleep
    • Whether Delirium Affects Reported Subjective Sleep Quality Remains Unclear
    • Although an Association Between Sleep Quality and Delirium Occurrence Exists in Critically Ill Adults, a Causal Relationship Has Not Been Established
  • Influence of Mechanical Ventilation on Sleep (Ungraded Statement)
    • Use of Mechanical Ventilation in Critically Ill Adults May Worsen Sleep Fragmentation, Sleep Architecture, and Circadian Rhythm (Daytime Sleep), as Compared to Normal Sleep, But These Effects are Often Variable and Have Not Yet Been Fully Investigated
    • Use of Mechanical Ventilation (vs Periods without Mechanical Ventilation) in Patients with Respiratory Failure May Improve Sleep Efficiency and Decrease Sleep Fragmentation, But the Data are Limited
    • Unclear Association Between Sleep Quality and Duration of Mechanical Ventilation, Length of ICU Stay, and ICU Mortality in Critically Ill Adults
    • Assist-Control Ventilation is Recommended at Night (vs Pressure Support Ventilation) for Improving Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
    • In Patient Requiring Noninvasive Positive-Pressure Ventilation (NIPPV), Either an NIPPV-Dedicated Ventilator or a Standard ICU Ventilator May Be Used for Critically Ill Adults to Improve Sleep (Conditional Recommendation, Very Low Quality of Evidence)
  • Unusual Sleep Patterns (Ungraded Statement)
    • The Prevalence of Unusual or Dissociated Sleep Patterns is Highly Variable and Depends on Patient Characteristics
  • Risk Factors (Ungraded Statement)
    • Patients Who Report Poor Quality Sleep and/or Use of a Pharmacologic Sleep Aid at Home are More Likely to Report Poor Quality Sleep in the ICU
    • Pain, Environmental Stimuli, Healthcare-Related Interruptions, Psychologic Factors, Respiratory Factors, and Medications Each Affect Sleep Quality in the ICU: see above
  • Monitoring of Sleep in the ICU
    • Clinical Physiologic Sleep Monitoring is Not Routinely Recommended in Critically Ill Adults (Conditional Recommendation, Very Low Quality of Evidence)
  • Other Adjunctive Therapies to Improve Sleep in the ICU
    • Aromatherapy, Acupressure, and Music at Night are Not Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence for Aromatherapy and Acupressure, Very Low Quality of Evidence for Music)
    • Noise/Light Reduction Strategies are Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
    • No Recommendation Regarding the Use of Melatonin to Improve Sleep in Critically Ill Adults (No Recommendation, Very Low Quality of Evidence)
    • Propofol is Not Recommended to Improve Sleep in Critically Ill Adults (Conditional Recommendation, Low Quality of Evidence)
    • No Recommendation Regarding the Use of Dexmedetomidine at Night to Improve Sleep in Critically Ill Adults (No Recommendation, Low Quality of Evidence)
    • Use of a Sleep-Promoting, Multicomponent Protocol is Recommended in Critically Ill Adults (Conditional Recommendation, Very Low Quality of Evidence)
  • Outcomes
    • The Effects of Sleep Quality and Circadian Rhythm Alterations on Outcomes in Critically Ill Patients After ICU Discharge are Unknown

Swallowing/Speech Impairment

Epidemiology
  • Swallowing/Speech Impairment is Common Following Extubation: occurs in approximately 50% of patients (range: 3-62%) (Chest, 2010) [MEDLINE]
    • However, Clinically-Significant Aspiration is Far Less Common
Mechanisms
  • Laryngeal Injury: likely mechanism for speech impairment
Clinical
Treatment
  • Formal Swallowing Evaluation (Fiberoptic Endoscopic Evaluation of Swallowing/FEES, Barium Swallowing Study, etc) is Generally Recommended for Patients Who Have Been Intubated for ≥7 Days (or Who Have Other Risk Factors for Dysphagia)
  • Usually Resolves Spontaneously Over Time

Temporomandibular Joint Dislocation (see Temporomandibular Joint Dislocation)

Mechanisms
  • Due to Excessive Force Used to Open the Mouth During Intubation

Tracheobronchial Wall Injury

Clinical
  • Bronchial Mucosal Injury: may result in hemoptysis from the site of mucosal injury
    • Bronchial Wall Mucosal Injury May Occur with Inadvertent Mainstem Intubation with a Single Lumen Tube or with Standard Use of a Double-Lumen Tube (Where the Tube Tip is Placed in Either the Right or Left Mainstem Bronchus)
  • Tracheal Mucosal Injury: may result in hemoptysis from the site of mucosal injury
  • Tracheal Perforation (see Tracheal Perforation)
  • Tracheoesophageal Fistula (see Tracheoesophageal Fistula)

Ventilator-Associated Pneumonia (VAP)/Ventilator-Associated Tracheobronchitis (see Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia)

Mechanisms
  • Bacterial Biofilm Formation within the Lumen of the Endotracheal Tube: occurs within hours of intubation

Ventilator-Associated Sinusitis (see Acute Rhinosinusitis)

Mechanisms
  • Impairment of Sinus Drainage, Resulting in Sinusitis

Ventilator-Induced Diaphragmatic Dysfunction (VIDD)

Mechanism
  • Diaphragmatic Muscle Atrophy
    • Diaphragmatic Proteolysis May Develop within the First Day of Mechanical Ventilation (N Engl J Med, 2008) [MEDLINE] (Am J Respir Crit Care Med, 2011) [MEDLINE]
    • Diaphragmatic Proteolysis Appears to Be Mediated Via Oxidative Stress-Induced Mitochondrial Dysfunction (Am J Respir Crit Care Med, 2012) [MEDLINE]
Diagnosis
  • Diaphragmatic Atrophy Can Be Identified by Diaphragmatic Ultrasound (Thorax, 2014) [MEDLINE]
Clinical
  • Diaphragmatic Thickening Can Predict Weaning Success (Thorax, 2014) [MEDLINE]
  • Study of Association of Ventilator-Associated Diaphragmatic Atrophy with Clinical Outcomes (Am J Respir Crit Care Med, 2018) [MEDLINE]: n = 191
    • Diaphragmatic Thickness Decreased >10% in 41% of Patients by Median Day 4 (Interquartile Range: 3-5)
    • Decreased Diaphragmatic Thickness (Due to Abnormally Low Respiratory Effort) was Associated with Decreased Daily Probability of Liberation from Mechanical Ventilation (Adjusted Hazard Ratio 0.69; 95% CI: 0.54-0.87; Per 10% Decrease), Prolonged ICU Admission (Adjusted Duration Ratio 1.71; 95% CI: 1.29-2.27), and a Higher Risk of Complications (Adjusted Odds Ratio 3.00; 95% CI: 1.34-6.72)
    • Increased Diaphragmatic Thickness (Due to Excessive Inspiratory Effort) (n = 47; 24%) Also Predicted Prolonged Mechanical Ventilation (Adjusted Duration Ratio 1.38; 95% CI: 1.00-1.90)
    • Patients with Thickening Fraction Between 15-30% (Similar to Breathing at Rest) During the First 3 Days Had the Shortest Duration of Mechanical Ventilation
Management
  • Unknown

Ventilator-Induced Lung Injury (VILI)/Barotrauma

  • See Above

Vocal Cord Granuloma (see Vocal Cord Granulomas)

Epidemiology
  • Vocal Cord Granuloma(s) May Occur in 30-40% of Patients Intubated for >3-4 Days (Intensive Care Med, 2010) [MEDLINE]
  • Duration of Intubation and Severity of Initial Laryngeal Injury Do Not Predict the Formation of Vocal Cord Granulomas (Am Rev Respir Dis, 1992) [MEDLINE]
Diagnosis
Physiology
  • Likely a Consequence of Prior Inflammation/Ulceration
Clinical
  • Hoarseness (see Hoarseness): hoarseness persisting for >7-10 days after extubation is suggestive of the diagnosis
Treatment
  • May Resolve Spontaneously in Some Cases (Crit Care Med, 1983) [MEDLINE]
  • Surgical Resection is Often Required

Vocal Cord Paralysis

Epidemiology
  • Occurs in <1% of Intubations
  • Risk Factors for Vocal Cord Paralysis (Br J Anaesth, 2007) [MEDLINE]
    • Age ≥50 y/o: 3-fold increased risk
    • Intubation ≥3-6 hrs: 2-fold increased risk
    • Intubation ≥6 hrs: 15-fold increased risk
    • Diabetes Mellitus (see Diabetes Mellitus): 2-fold increased risk
    • Hypertension (see Hypertension): 2-fold increased risk
Clinical

Vocal Cord Ulceration

Epidemiology
  • Occurs in Approximately 33% of Cases
  • Most Commonly Occurs with Intubations Lasting >4 Days (Intensive Care Med, 2010) [MEDLINE]
Physiology
  • Direct Pressure on Vocal Cords (with/without Associated Inflammation): usually occurs at the posteromedial aspect of the vocal cords
Diagnostic
Clinical
Treatment
  • Vocal Cord Ulcers Usually Resolve Spontaneously, But May Progress to Granulomas, Nodules, Interarytenoid Adhesions (Crit Care Med, 1983) [MEDLINE]

Other Complications

Decubitus Ulcer (see Decubitus Ulcer)
  • Mechanisms
    • Prolonged Immobilization
    • Elevation of the Head of the Bed (Which is Standardly Used in the Mechanically-Ventilated Patient to Decrease the Risk of Aspiration) is Associated with Increased Risk of Sacral Decubitus Ulcers (Crit Care Med, 2008) [MEDLINE]
Deep Venous Thrombosis (DVT) (see Deep Venous Thrombosis)
  • Epidemiology
    • Prolonged Immobilization Associated with Mechanical Ventilation is Associated with an Increased Risk of Deep Venous Thrombosis
    • Additionally, Deep Venous Thrombosis is Common in Mechanically-Ventilated Patients, Despite the Use of Pharmacologic Prophylaxis (J Thromb Thrombolysis, 2017) [MEDLINE]
Induction of Inflammatory Response
  • Mechanism
    • Positive-Pressure Mechanical Ventilation Induces an Inflammatory Cytokine Response (in the Bloodstream and Bronchoalveolar Lavage Fluid), Which May Be Attenuated by a the Use of Low Tidal Volume/High PEEP Strategy to Minimize Overdistention and Recruitment/Derecruitment of the Lung (JAMA, 1999) [MEDLINE]
Insulin Resistance
  • Epidemiology
    • Prolonged Bedrest Associated with Mechanical Ventilation Has Been Associated with the Development of Insulin Resistance (Arterioscler Thromb Vasc Biol, 2007) [MEDLINE]
Joint Contractures
  • Epidemiology
    • Prolonged Bed Rest is Associated with the Development of Joint Contractures (CMAJ, 2008) [MEDLINE]
Tracheal Bacterial Translocation into the Bloodstream
  • Mechanism
    • Positive-Pressure Mechanical Ventilation Has Been Demonstrated to Induce Translocation of Tracheal Bacteria into the Bloodstream in Animal Studies (Especially with High Tidal Volumes and Low PEEP) (Crit Care Med, 1997) [MEDLINE]

Late Adverse Effects/Complications (Manifest Within Weeks-Months After Intubation)

Laryngotracheal Stenosis (see Tracheal Stenosis)

Epidemiology
  • Generally Occurs Weeks-Months After Intubation
  • Incidence: 1-21% (Ann Otol Rhinol Laryngol, 2007) [MEDLINE]
  • Risk Factors (Ann Otol Rhinol Laryngol, 2007) [MEDLINE]
    • Prior Irradiation for Oropharyngeal/Laryngeal Tumor
    • Prior Non-Airway Surgery
    • Prolonged Intubation >7 Days: rarely occurs in those intubated for <3 days
Physiology
  • Laryngeal (Glottic) Stenosis: due to pressure from the endotracheal tube itself with local ischemia, inflammation, tissue necrosis, and scarring
    • Usual Location: posterior glottis and interarytenoid regions (where the endotracheal tube exerts the most pressure)
  • Tracheal Stenosis: due to high endotracheal tube cuff pressure (at 20 cm H20, cuff pressure will exceed the mean capillary pressure in the mucosa), with obstruction of capillary blood flow and associated ischemia, inflammation, erosion of the mucosa, tissue necrosis, distorted tracheal architecture, and scarring
    • Usual Location/Appearance: web-like stenosis at the cuff site
      • In Contrast, Tracheal Stenosis Associated with Tracheostomy Typically Occurs Around the Tracheal Stoma (see Tracheostomy)
Diagnosis
Clinical
  • Failure to Wean from Mechanical Ventilation: in patients on mechanical ventilation
  • Subacute/Progressive Dyspnea (see Dyspnea)
    • Usually Becomes Symptomatic Approximately 5 wks-Months After Extubation
Treatment
  • Rigid Bronchoscopy with Dilation/Laser Resection/Stenting (see Bronchoscopy): may be required for tracheal stenosis
  • Mitomycin C (see Mitomycin): has been used to prevent tracheal restenosis after local procedures
  • Surgical Resection: may be required in refractory cases of tracheal stenosis

Laryngotracheomalacia (see Tracheobronchomalacia)

Epidemiology
  • Well-Known Complication of Prolonged Endotracheal Intubation (Aust N Z J Surg, 1976) [MEDLINE]
  • Generally Occurs Weeks-Months After Endotracheal Intubation
Mechanism
  • Thinning and/or Destruction of Tracheal Cartilage Due to Increased Endotracheal Tube Cuff Pressure

Tracheoarterial Fistula (see Tracheoinnominate Artery Fistula)

Epidemiology
  • Cases Have Been Reported with Prolonged Endotracheal Intubation: although it has more commonly been reported with tracheostomy (see Tracheostomy)
Mechanism
  • Erosion Through Tracheal Wall into Innominate Artery
Clinical
  • Tracheoinnominate Artery Fistula: usually

Tracheoesophageal Fistula (see Tracheoesophageal Fistula)

Epidemiology
  • While Rare with Endotracheal Intubation, Reported Cases Have Been Observed in Patients with Prolonged Intubation (Aust N Z J Surg, 1976) [MEDLINE]
    • Risk Factors (Chest Surg Clin N Am, 1996) [MEDLINE]
      • Corticosteroids (see Corticosteroids): possible risk factor
      • Diabetes Mellitus (see Diabetes Mellitus): possible risk factor
      • Excessive Mobility of the Endotracheal Tube
      • High Airway Pressure
      • High Endotracheal Tube Cuff Pressure: main risk factor
      • Prolonged Duration of Mechanical Ventilation
      • Use of Nasogastric Tube (see Nasogastric-Orogastric Tube): possible risk factor
Mechanism
  • Erosion of the Endotracheal Tube Tip/Cuff into the Posterior Wall of the Trachea, Fistulizing into the Esophagus
Clinical
  • Air Leak from Ventilator Circuit
  • Gastric Distention
  • Presence of Tube Feedings in Tracheal Secretions
  • Recurrent Aspiration Pneumonia (see Aspiration Pneumonia)

References

General

  • Safe intrahospital transport of critically ill ventilator-dependent patients. Chest 1989; 96:631-635 [MEDLINE]
  • Airway considerations in the management of patients requiring long-term endotracheal intubation. Anesth Analg. 1992;74(2):276 [MEDLINE]
  • Unplanned extubations in the adult intensive care unit. Am J Respir Crit Care Med 1998; 157:1131-1137 [MEDLINE]
  • Death and other complications of emergency airway management in critically ill adults. Anesthesiology 1995; 82:367-376 [MEDLINE]
  • Bedside procedures: solutions to the pitfalls of intrahospital transport. Crit Care Clin 2000; 16:1-6 [MEDLINE]
  • Prediction of difficult mask ventilation.  Anesthesiology 2000;92:1229–1236 [MEDLINE]
  • Difficult airway management in the emergency department. J Emerg Med. 2002 Jan;22(1):31-48 [MEDLINE]
  • Clinical practice guidelines for sustained neuromuscular blockade in the adult critically ill patient. Crit Care Med. 2002 Jan;30(1):142-56 [MEDLINE]
  • Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement. Emerg Med J 2003: 20: 265-266 [MEDLINE]
  • The assessment of three methods to verify tracheal tube placement in the emergency setting. Resuscitation 2003; 56:153-157 [MEDLINE]
  • The effectiveness of out-of-hospital use of continuous end-tidal carbon dioxide monitoring on the rate of unrecognized misplaced intubation within a regional emergency medical services system. Ann Emerg Med 2005; 45:497-503 [MEDLINE]
  • Clinical review: management of difficult airways.  Crit Care 2006;10:243.  doi: 10.1186/cc5112 [MEDLINE]
  • Incidence and predictors of difficult or impossible mask ventilation.  Anesthesiology 2006;105:885–891 [MEDLINE]
  • Caution when using colorimetry to confirm endotracheal intubation. Anesth Analg 2007;104:738 [MEDLINE]
  • 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Part 8: adult advanced cardiovascular life support. Circulation 2010; 122(18 Suppl 3):S729-S767 [MEDLINE]
  • Airway management in critically ill patients.  Lung  2011; 189:181-192 [MEDLINE]
  • Emergency airway management: the difficult airway.  Emerg Med Clin North Am  2012; 30:401-420 [MEDLINE]
  • Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology. 2013;118:251–270 [MEDLINE]
  • The effect of body mass index on intubation success rates and complications during emergency airway management. Intern Emerg Med. 2013 Feb;8(1):75-82. Epub 2012 Nov 25 [MEDLINE]
  • Video laryngoscopy versus direct laryngoscopy for orotracheal intubation in the intensive care unit: a systematic review and meta-analysis. Intensive Care Med. 2014 May;40(5):629-39. doi: 10.1007/s00134-014-3236-5. Epub 2014 Feb 21 [MEDLINE]
  • Transnasal humidified rapid-insufflation ventilatory exchange (THRIVE): a physiological method of increasing apnoea time in patients with difficult airways. Anaesthesia 2015;70:323-9 [MEDLINE]
  • Use of high-flow nasal cannula oxygen therapy to prevent desaturation during tracheal intubation of intensive care patients with mild-to-moderate hypoxemia. Crit Care Med. 2015;43:574–583 [MEDLINE]
  • Heated humidified high-flow nasal oxygen in adults: mechanisms of action and clinical implications. Chest. 2015;148(1):253–261 [MEDLINE]
  • First Pass Success Without Hypoxemia Is Increased With the Use of Apneic Oxygenation During Rapid Sequence Intubation in the Emergency Department. Acad Emerg Med. 2016 Jun;23(6):703-10. Epub 2016 May 13 [MEDLINE]

Assessment for Upper Airway Obstruction

  • A life-saving maneuver to prevent food-choking. JAMA. 1975;234(4):398 [MEDLINE]
  • Heimlich versus a slap on the back. N Engl J Med. 1979;300(17):990 [MEDLINE]
  • The choking controversy: critique of evidence on the Heimlich maneuver. Crit Care Med. 1979;7(10):475 [MEDLINE]
  • Chest compression–an alternative to the Heimlich manoeuver? Resuscitation. 1992;24(1):91 [MEDLINE]
  • Traumatic rupture of the stomach secondary to Heimlich maneuver. Am J Emerg Med. 1993;11(6):611 [MEDLINE]
  • Assessment of upper airway anatomy in awake, sedated and anaesthetised patients using magnetic resonance imaging. Anaesth Intensive Care. 1994;22(2):165 [MEDLINE]
  • Magnetic resonance imaging of the upper airway. Effects of propofol anesthesia and nasal continuous positive airway pressure in humans. Anesthesiology. 1996;84(2):273 [MEDLINE]
  • Gastric rupture secondary to successful Heimlich manoeuvre. Postgrad Med J. 1998;74(876):609 [MEDLINE]
  • Airway pressure with chest compressions versus Heimlich manoeuvre in recently dead adults with complete airway obstruction. Resuscitation. 2000;44(2):105 [MEDLINE]
  • Rupture of the lesser gastric curvature after a Heimlich maneuver. Surg Endosc. 2003;17(9):1495 [MEDLINE]
  • Part 4: CPR overview: 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2010;122(18 Suppl 3):S676 [MEDLINE]
  • Part 5: Adult Basic Life Support and Cardiopulmonary Resuscitation Quality: 2015 American Heart Association Guidelines Update for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care. Circulation. 2015;132(18 Suppl 2):S414 [MEDLINE]

Airway Maneuvers

  • Resuscitation–opening the airway. A comparative study of techniques for opening an airway obstructed by the tongue. JACEP. 1976;5(8):588 [MEDLINE]
  • The effect of airway maneuvers on the unstable C1-C2 segment. A cadaver study. Spine (Phila Pa 1976). 1997;22(11):1215 [MEDLINE]
  • Cervical spine motion during airway management: a cinefluoroscopic study of the posteriorly destabilized third cervical vertebrae in human cadavers. Anesth Analg. 2000;91(5):1274 [MEDLINE]
  • Effectiveness of the jaw-thrust maneuver in opening the airway: a flexible fiberoptic endoscopic study. ORL J Otorhinolaryngol Relat Spec. 2005;67(1):39 [MEDLINE]

Airway Adjuncts

  • The nasopharyngeal airway. Assessment of position by fibreoptic laryngoscopy. Anaesthesia. 1993;48(7):575 [MEDLINE]
  • The nasopharyngeal airway: dispelling myths and establishing the facts. Emerg Med J. 2005;22(6):394 [MEDLINE]

Bag-Valve-Mask Ventilation

  • Simultaneous aortic, jugular bulb, and right atrial pressures during cardiopulmonary resuscitation in humans. Insights into mechanisms. Circulation. 1989;80(2):361 [MEDLINE]
  • Comparison of self-inflating bags with anesthesia bags for bag-mask ventilation in the pediatric emergency department. Pediatr Emerg Care. 1997;13(5):312 [MEDLINE]
  • Hyperventilation-induced hypotension during cardiopulmonary resuscitation. Circulation. 2004;109(16):1960 [MEDLINE]
  • Death by hyperventilation: a common and life-threatening problem during cardiopulmonary resuscitation. Crit Care Med. 2004;32(9 Suppl):S345 [MEDLINE]
  • The effect of leaving dentures in place on bag-mask ventilation at induction of general anesthesia. Anesth Analg. 2007;105(2):370 [MEDLINE]
  • A two-handed jaw-thrust technique is superior to the one-handed “EC-clamp” technique for mask ventilation in the apneic unconscious person. Anesthesiology. 2010;113(4):873 [MEDLINE]
  • Face mask ventilation in edentulous patients: a comparison of mandibular groove and lower lip placement. Anesthesiology. 2010;112(5):1190 [MEDLINE]
  • Efficacy of facemask ventilation techniques in novice providers. Clin Anesth. 2013 May;25(3):193-7 [MEDLINE]
  • Difficult face-mask ventilation and difficult laryngoscopy Anesthesiology. 2014 Aug;121(2):421-2. doi: 10.1097/ALN.0000000000000293 [MEDLINE]
  • Optimizing Mask Ventilation: Literature Review and Development of a Conceptual Framework. Respir Care. 2015 Dec;60(12):1834-40. doi: 10.4187/respcare.04183 [MEDLINE]

Body Position

  • Analysis of the forces and position required for direct laryngoscopic exposure of the anterior vocal folds. Ann Otol Rhinol Laryngol. 1999;108(8):715 [MEDLINE]
  • Head and neck elevation beyond the sniffing position improves laryngeal view in cases of difficult direct laryngoscopy. J Clin Anesth. 2002;14(5):335 [MEDLINE]
  • Head-elevated laryngoscopy position: improving laryngeal exposure during laryngoscopy by increasing head elevation. Ann Emerg Med. 2003;41(3):322 [MEDLINE]
  • Laryngoscopy and morbid obesity: a comparison of the “sniff” and “ramped” positions. Obes Surg. 2004;14(9):1171 [MEDLINE]
  • Head-Elevated Patient Positioning Decreases Complications of Emergent Tracheal Intubation in the Ward and Intensive Care Unit. Anesth Analg. 2016 Apr;122(4):1101-7 [MEDLINE]

Cricoid Pressure (Sellick Maneuver)

  • Best evidence topic report. Cricoid pressure in emergency rapid sequence induction. Emerg Med J. 2005;22(11):815 [MEDLINE]

Rapid Sequence Intubation (RSI)

  • A comparison of blind nasotracheal and succinylcholine-assisted intubation in the poisoned patient. Ann Emerg Med. 1987;16(6):650 [MEDLINE]
  • Decreased circulation time in the upper limb reduces the lag time of the finger pulse oximeter response. Can J Anaesth. 1992 Jan;39(1):87-9 [MEDLINE]
    • Rapid-sequence intubation in head trauma. Ann Emerg Med. 1993;22(6):1008 [MEDLINE]
  • Critical hemoglobin desaturation will occur before return to an unparalyzed state following 1 mg/kg intravenous succinylcholine. Anesthesiology. 1997;87(4):979 [MEDLINE]
  • Airway management in the emergency department: a one-year study of 610 tracheal intubations. Ann Emerg Med. 1998;31(3):325 [MEDLINE]
  • Complications of emergency intubation with and without paralysis. Am J Emerg Med. 1999;17(2):141 [MEDLINE]
  • The failed intubation attempt in the emergency department: analysis of prevalence, rescue techniques, and personnel. J Emerg Med. 2002;23(2):131 [MEDLINE]
  • Airway management by US and Canadian emergency medicine residents: a multicenter analysis of more than 6,000 endotracheal intubation attempts. Ann Emerg Med. 2005;46(4):328 [MEDLINE]
  • Preoxygenation and prevention of desaturation during emergency airway management. Ann Emerg Med. 2012 Mar;59(3):165-75.e1 [MEDLINE]
  • Neuromuscular blocking agent administration for emergent tracheal intubation is associated with decreased prevalence of procedure-related complications. Crit Care Med. 2012 Jun;40(6):1808-1 [MEDLINE]
  • Neuromuscular blockade improves first-attempt success for intubation in the intensive care unit. A propensity matched analysis. Ann Am Thorac Soc. 2015;12(5):734 [MEDLINE]
  • Techniques, success, and adverse events of emergency department adult intubations. Ann Emerg Med. 2015 Apr;65(4):363-370.e1 [MEDLINE]
  • The Physiologically Difficult Airway. West J Emerg Med. 2015;16(7):1109 [MEDLINE]
  • The effectiveness of rapid sequence intubation (RSI) versus non-RSI in emergency department: an analysis of multicenter prospective observational study. Int J Emerg Med. 2017;10(1):1 [MEDLINE]
  • Management of Patients with Predicted Difficult Airways in an Academic Emergency Department. J Emerg Med. 2017;53(2):163 [MEDLINE]

Awake Laryngoscopy

  • Endotracheal intubation in the ICU. Crit Care. 2015;19:258 [MEDLINE]
  • Awake Laryngoscopy in the Emergency Department. J Emerg Med. 2017;52(3):324 [MEDLINE]

Confirmation of Endotracheal Tube Placement

  • Accidental intubation of the oesophagus. Anaesth Intensive Care. 1980;8(2):183 [MEDLINE]
  • End-tidal CO2 as a guide to successful cardiopulmonary resuscitation: a preliminary report. Crit Care Med. 1985;13(11):910 [MEDLINE]
  • Esophageal intubation: a review of detection techniques. Anesth Analg. 1986;65(8):886 [MEDLINE]
  • Unrecognized endobronchial intubation of emergency patients. Ann Emerg Med. 1989;18(8):853 [MEDLINE]
  • A comparative study of methods of detection of esophageal intubation. Anesth Analg. 1989;69(5):627 [MEDLINE]
  • Multicenter study of a portable, hand-size, colorimetric end-tidal carbon dioxide detection device. Ann Emerg Med. 1992 May;21(5):518-23 [MEDLINE]
  • Women are at greater risk than men for malpositioning of the endotracheal tube after emergent intubation. Crit Care Med. 1994;22(7):1127 [MEDLINE]
  • Proper depth placement of oral endotracheal tubes in adults prior to radiographic confirmation. Acad Emerg Med. 1995;2(1):20 [MEDLINE]
  • Use of tube condensation as an indicator of endotracheal tube placement. Ann Emerg Med. 1998;31(5):575 [MEDLINE]
  • Comparison of three different methods to confirm tracheal tube placement in emergency intubation. Intensive Care Med. 2002;28(6):701 [MEDLINE]
  • Towards evidence based emergency medicine: best BETs from the Manchester Royal Infirmary. Colourimetric CO(2) detector compared with capnography for confirming ET tube placement. Emerg Med J. 2003 May;20(3):265-6 [MEDLINE]
  • An assessment of a tracheal tube introducer as an endotracheal tube placement confirmation device. Am J Emerg Med. 2005;23(6):754 [MEDLINE]
  • Endobronchial intubation detected by insertion depth of endotracheal tube, bilateral auscultation, or observation of chest movements: randomised trial. BMJ. 2010;341:c5943 [MEDLINE]
  • Ultrasonography in the management of the airway. Acta Anaesthesiol Scand. 2011 Nov;55(10):1155-73. Epub 2011 Sep 7 [MEDLINE]
  • Tracheal rapid ultrasound exam (T.R.U.E.) for confirming endotracheal tube placement during emergency intubation. Resuscitation. 2011 Oct;82(10):1279-84. Epub 2011 Jun 1 [MEDLINE]
  • Transtracheal ultrasound for verification of endotracheal tube placement: a systematic review and meta-analysis. Can J Anaesth. 2015 Apr;62(4):413-23. Epub 2014 Dec 24 [MEDLINE]
  • Ultrasonography for confirmation of endotracheal tube placement: a systematic review and meta-analysis. Resuscitation. 2015;90:97 [MEDLINE]
  • Auscultation versus Point-of-care Ultrasound to Determine Endotracheal versus Bronchial Intubation: A Diagnostic Accuracy Study. Anesthesiology. 2016 May;124(5):1012-20 [MEDLINE]

Adverse Effects/Complications

  • Ulcerative tracheo-oesophageal fistula during treatment by tracheostomy and intermittent positive pressure ventilation. Thorax. 1972;27(3):338 [MEDLINE]
  • Tracheal injury following prolonged intubation. Aust N Z J Surg. 1976 Feb;46(1):18-25 [MEDLINE]
  • Intubation lesions of the larynx. Br J Anaesth. 1978;50(6):587 [MEDLINE]
  • Postoperative sore throat: influence of tracheal tube lubrication versus cuff design. Can Anaesth Soc J. 1980;27(2):156 [MEDLINE]
  • Laryngeal injuries secondary to nasogastric tubes. Ann Otol Rhinol Laryngol. 1981;90(5 Pt 1):469 [MEDLINE]
  • The influence of endotracheal tube cuff design and cuff lubrication on postoperative sore throat. Anesthesiology. 1983;58(4):376 [MEDLINE]
  • Laryngotracheal injury due to endotracheal intubation: incidence, evolution, and predisposing factors. A prospective long-term study. Crit Care Med. 1983;11(5):362 [MEDLINE]
  • True vocal cord paralysis following intubation. Laryngoscope. 1985;95(11):1352 [MEDLINE]
  • Correlation of endotracheal tube size with sore throat and hoarseness following general anesthesia. Anesthesiology. 1987 Sep;67(3):419-21 [MEDLINE]
  • Laryngeal complications of prolonged intubation. Chest. 1989;96(4):877 [MEDLINE]
  • Anesthesia-induced dental injury. Int Anesthesiol Clin. 1989;27(2):120 [MEDLINE]
  • Unsuspected cervical fractures: a common problem in ankylosing spondylitis. Anesthesiology. 1989;70(5):869 [MEDLINE]
  • Tracheoesophageal fistula formation in intubated patients. Risk factors and treatment with high-frequency jet ventilation. Chest. 1990;98(1):161 [MEDLINE]
  • Swallowing disorders in patients with prolonged orotracheal intubation or tracheostomy tubes. Crit Care Med. 1990;18(12):1328 [MEDLINE]
  • Adverse respiratory events infrequently leading to malpractice suits. A closed claims analysis. Anesthesiology. 1991;75(6):932 [MEDLINE]
  • Surgical considerations in tracheal stenosis. Laryngoscope. 1992 Mar;102(3):237-43 [MEDLINE]
  • Resolution of laryngeal injury following translaryngeal intubation. Am Rev Respir Dis. 1992;145(2 Pt 1):361 [MEDLINE]
  • Evaluation of risk factors for laryngeal edema after tracheal extubation in adults and its prevention by dexamethasone. A placebo-controlled, double-blind, multicenter study. Anesthesiology. 1992;77(2):245 [MEDLINE]
  • Prophylactic laryngo-tracheal aerosolized lidocaine against postoperative sore throat. Acta Anaesthesiol Scand. 1992;36(6):505 [MEDLINE]
  • Massive airway leaks: an analysis of the role of endotracheal tubes. Crit Care Med. 1993;21(4):518 [MEDLINE]
  • Mediastinitis and sepsis syndrome following intubation. Anaesthesia. 1994;49(10):883 [MEDLINE]
  • Risk factors associated with prolonged intubation and laryngeal injury. Otolaryngol Head Neck Surg. 1994;111(4):453 [MEDLINE]
  • [A survey of perioperative bronchospasm in 105 patients with reactive airway disease]. Masui. 1995;44(3):396 [MEDLINE]
  • Management of acquired tracheoesophageal fistula. Chest Surg Clin N Am. 1996 Nov;6(4):819-36 [MEDLINE]
  • Gastroesophageal reflux in patients with subglottic stenosis. Arch Otolaryngol Head Neck Surg. 1998 May;124(5):551-5 [MEDLINE]
  • Airway injury during anesthesia: a closed claims analysis. Anesthesiology. 1999;91(6):170 [MEDLINE]
  • Postextubation fiberoptic endoscopic evaluation of swallowing after prolonged endotracheal intubation: a randomized, prospective trial. Crit Care Med. 2001;29(9):1710 [MEDLINE]
  • Postoperative sore throat after ambulatory surgery. Br J Anaesth. 2002;88(4):582 [MEDLINE]
  • Tracheoesophageal fistula. Chest Surg Clin N Am. 2003 May;13(2):271-89 [MEDLINE]
  • Vocal fold injury following endotracheal intubation. J Laryngol Otol. 2005 Oct;119(10):825-7 [MEDLINE]
  • Association of airway abnormalities and risk factors in 37 subglottic stenosis patients. Otolaryngol Head Neck Surg. 2006 Sep;135(3):434-7 [MEDLINE]
  • Review of tracheo-esophageal fistula associated with endotracheal intubation. J Surg Educ. 2007 Jul-Aug;64(4):237-40 [MEDLINE]
  • Risk factors for adult laryngotracheal stenosis: a review of 74 cases. Ann Otol Rhinol Laryngol. 2007 Mar;116(3):206-10 [MEDLINE]
  • Short-term effects of endotracheal intubation on voice. J Voice. 2007 Nov;21(6):762-8 [MEDLINE]
  • Age and comorbidity as risk factors for vocal cord paralysis associated with tracheal intubation. Br J Anaesth. 2007 Apr;98(4):524-30 [MEDLINE]
  • Effect of positive expiratory pressure and type of tracheal cuff on the incidence of aspiration in mechanically ventilated patients in an intensive care unit. Crit Care Med. 2008;36(2):409 [MEDLINE]
  • CDC/NHSN surveillance definition of health care-associated infection and criteria for specific types of infections in the acute care setting. Am J Infect Control. 2008;36(5):309 [MEDLINE]
  • Spiral CT virtual bronchoscopy with multiplanar reformatting in the evaluation of post-intubation tracheal stenosis: comparison between endoscopic, radiological and surgical findings. Eur Arch Otorhinolaryngol. 2009;266(6):863 [MEDLINE]
  • Incidence and impact of dysphagia in patients receiving prolonged endotracheal intubation after cardiac surgery. Can J Surg. 2009;52(2):119 [MEDLINE]
  • The incidence of dysphagia following endotracheal intubation: a systematic review. Chest. 2010;137(3):665 [MEDLINE]
  • Postoperative patient complaints: a prospective interview study of 12,276 patients. J Clin Anesth. 2010;22(1):13 [MEDLINE]
  • Cost analysis of intubation-related tracheal injury using a national database. Otolaryngol Head Neck Surg. 2010 Jul;143(1):31-6. doi: 10.1016/j.otohns.2009.11.004 [MEDLINE]
  • Endotracheal tube size and sore throat following surgery: a randomized-controlled study. Acta Anaesthesiol Scand. 2010 Feb;54(2):147-53 [MEDLINE]
  • Post-intubation laryngeal injuries and extubation failure: a fiberoptic endoscopic study. Intensive Care Med. 2010 Jun;36(6):991-8. Epub 2010 Mar 18 [MEDLINE]
  • Postextubation obstructive pseudomembranes: a case series and review of a rare complication after endotracheal intubation. Lung. 2011 Feb;189(1):81-6. Epub 2010 Nov 17 [MEDLINE]
  • Laryngeal injury from prolonged intubation: a prospective analysis of contributing factors. Laryngoscope. 2011;121(3):596 [MEDLINE]
  • Posttracheostomy tracheoesophageal fistula. J Anaesthesiol Clin Pharmacol. 2012 Jan;28(1):140-1 [MEDLINE]
  • Association between repeated intubation attempts and adverse events in emergency departments: an analysis of a multicenter prospective observational study. Ann Emerg Med. 2012 Dec;60(6):749-754.e2 [MEDLINE]
  • Endotracheal tube cuff leaks: causes, consequences, and management. Anesth Analg. 2013 Aug;117(2):428-34[MEDLINE]
  • Surgical Management of Benign Acquired Tracheoesophageal Fistulas: A Ten-Year Experience. Ann Thorac Surg. 2016;102(4):1081 [MEDLINE]
  • Incidence and risk factors of postoperative sore throat after endotracheal intubation in Korean patients. J Int Med Res. 2017;45(2):744 [MEDLINE]
  • Effect of Endotracheal Tube Cuff Shape on Postoperative Sore Throat After Endotracheal Intubation. Anesth Analg. 2017;125(4):1240 [MEDLINE]
  • The Effect of Zinc Lozenge on Postoperative Sore Throat: A Prospective Randomized, Double-Blinded, Placebo-Controlled Study. Anesth Analg. 2018;126(1):78 [MEDLINE]